View Full Version : Choosing a flat tappet cam for vortec 350


RockinZ
11-29-2008, 09:12:54 PM
Hi Everyone, I'm pretty new to this forum and being a chevy owner (mopars 25 years ago)
I am building my first engine.
it's meant for fun on the street and maybe a drag race here and there.

I have a '84 350 .020 over.
'96 Vortec heads 2.02 / 1.60 valves & ported
Flat top pistons with valve relief .025 in the hole
9.7 to 1 compression
Edelbrock performer 2116 intake
Qjet
stock converter (I think)
TH350 & 2.41:screwup: gear BUT planning 700r4 / 3.73 grear

I had decided on a Voodoo 262 (60102), but then read a story on this forum about a lobe on this cam going flat after 3000 miles. Some say the aggressive lobe angles on these advanced cams cause a durability problem. I realize it's only one story, and I still want to try the Voodoo cam, but has anyone got a similar set-up? Any advice?

Thanks,
Kyle

Spot_remover
11-29-2008, 09:17:40 PM
I'm gonna run a small Thumpr in my 355 vortec. Should have it together in a couple of weeks i'll let you know how it does.

RockinZ
11-29-2008, 09:20:54 PM
I forgot to mention the vortecs have screw in studs and guideplates

andrewsreed
11-29-2008, 10:35:37 PM
get a roller cam... my vortect motor has a roller cam and it makes awesome power and will rev to the sky...

hardline_42
11-29-2008, 10:46:09 PM
How ported are the Vortecs? If the intake/exhaust flow ratio has changed from stock it may affect your cam choice. Otherwise, I would suggest the Comp Cams XE 268 if it's more street than strip.

RockinZ
11-29-2008, 10:58:52 PM
BLOCK: I made a mistake in the specs, my block is an '84. Not set-up for roller, and I don't want to get into modding the block.

PORTING: I don't know enough to tell you, I think they have just been smoothed out a little and the valves are bigger. My buddy who is an ex mechanic said that the port job was nice. That's all I know. There are pics in my gallery, but there a little low rez, I can post better if that helps.

CAM: I was staying away from the XE 268 because of the 110 lsa. I have been advised to look for 112 or higher to create better vacuum and torque on the bottom end. But I keep seeing it getting recommended everywhere. There's also the Crane PowerMax 272-2 pn114142, It has been recommended as well.

docwilcar
11-29-2008, 11:17:34 PM
Comp 268HE, Energizer 272, both on 110 lsa, will give you plenty of vacuum(15-16"). If you want a rump rump idle that is still very streetable, try the Crane Energizer 100172 218-218 .454 lift on a 106 lsa. 14" of vacuum at 1000 and will sound like you have a thumper cam in it. May need a mild stall with a T350 or 700r4. My buddy just put one in his 8.5 cr crate motor and the cam is very strong in the low and midrange and pulls all the way to 5600 no problem with stock springs.

Incenter12
11-29-2008, 11:40:10 PM
I've got 906 vortecs on my 350 with dished pistons and I threw in the Comp 268H with the performer intake. I need a little higher stall for my TH350 and I'm thinking of bumping the 3.08 out back up to 3.73.

Here's a video from break-in,

http://www.youtube.com/watch?v=RtJ8Fw1_y9M

GoldenOne7710
11-30-2008, 01:21:10 AM
Either the Crane, Comp, or Lunati cam in that same class will all perform close to the same. They will all have impressive that low-end grunt you desire. You may consider swapping your converter to a hair higher one.....maybe in the 2000-2200ish range. As for gears, I'd go with the 3.73 ONLY if you're definitely going with the 700R4. If you keep the TH350, a 3.42 would feel better (all around) for your package.

I may be wrong, but 9.2cr seems a little low for Vortecs and flat-tops....even WITH the valve reliefs. Are you sure that's right? Seems like it'd be closer to 9.5-9.7...

RockinZ
11-30-2008, 08:01:22 AM
You're right, the CR I got is 9.7, so much for regular octane!:eek:

RockinZ
11-30-2008, 09:20:29 AM
Thanks for the info so far. I would like to hear more from people running this kind of engine.

I took some up close shots of the heads, block, cylinders & intake.

You can see where the porting was done.
The pistons have pretty big valve reliefs, not sure how much ccs that is, my last 9.7 calc was with -5cc.

http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30004.jpg
http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30007.jpg
http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30010.jpg
http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30014.jpg
http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30016.jpg
http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30000.jpg
http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30011.jpg
http://i397.photobucket.com/albums/pp56/RockinZ/EnginePhotosNov30019.jpg

cmonson
11-30-2008, 09:46:32 AM
I am also running a vortec combo, and all I can say is that you will love it.

I too performed a port, polish and I did a bowl blend to accomodate the 2.02, 1.6 valves that were installed. I would HIGHLY suggest that you enlarge the pushrod holes. It is VERY easy to do... I am also assuming that you modded the vortecs for lift over .485 lift...

Also, if you install a .015 shim head gasket, your compression should be right at 10:1. I assume you also knocked off some material during decking which may even bring it above 10:1.

I would suggest you do the plenum mod as I did to help the top end of that eddy. Here is how it should look.
http://i54.photobucket.com/albums/g111/cmonson/4-20-08003.jpg


You mentioned going with a 112LSA cam for vacumn... I run a reed cam cut on a 108. I have NO issues with power brakes. I did have to mod the idle circuit of my qjet however. Below is my cam card. I run 1.6 ratio as well so my lift and duration is a little higher. INT=.512, EX=.518 duration is on the card.

http://i54.photobucket.com/albums/g111/cmonson/reedcams.png

fabio
11-30-2008, 11:48:43 AM
your combustion chambers are probably pretty small. Those valves have no dish in them like the stockers.

RockinZ
11-30-2008, 03:13:14 PM
Uh-oh... will I be filling up at the airport?

Jim Mac
11-30-2008, 03:16:21 PM
I bought the sealed power version of those pistons. going with vortecs too. I think in the northern site it show the compression to be 9.8 to 1 jim

cmonson
11-30-2008, 04:51:46 PM
Uh-oh... will I be filling up at the airport?

Being 25 in the holes, and most likely about 62cc chambers, using those stock 4 relief pistons, and a .015 shim head gasket, you will be very close to 10:1.

NO, you will not be filling up at an airport. Many people run 11:1 on cast iron heads and fill up on 93.

I run well over 10.5:1 on my vortec combo 350 and it runs great using 93oct gasoline.

RockinZ
11-30-2008, 06:02:18 PM
Hey Jim,
I would bet that my pistons are sealed power as well. When I tore it down I found out that the camshaft was a sealed power. There was probably a complete rebuild kit put into it.

RockinZ
11-30-2008, 10:26:03 PM
I just redid the calculation assuming 62 cc heads, 4.02 bore ,3.48 stroke, 4.1 gasket dia. x .041 compressed thickness, -5 valve relief, .025 in the hole.
9.93 to 1. Very close to 10 to 1 indeed! :smokin:

Is there anything I should reconsider for the cam?

RockinZ
11-30-2008, 10:29:06 PM
BTW did anyone notice that my Avatar's car is a Camaro?

cmonson
12-01-2008, 09:06:48 AM
use a metal shim (.015)head gasket, in lieu of the .041 stanard, that will bring you right at 10:1. Perfect for pump gas (93oct) and a great cam.

RockinZ
12-01-2008, 09:28:08 AM
Any suggestions for a cam?
Are the ones I'm looking at good choices?
Keeping it street.

Thanks

RockinZ
12-01-2008, 07:38:11 PM
cmonson, That Reed cam has a more symmetrical shape than the cams I have been looking at. I thought higher exhaust duration was good for vortecs. Is it because it's less of an issue with the porting and the big valves?

Doug Jaynes
12-01-2008, 09:35:05 PM
it most likely wont hurt a thing to run a cam with 10 or so more degrees exhaust duration. especially with a full exhaust on the car. The only way to really know whats best is to get it on a motor dyno and try a handful of cams. Not many people want to do that with a street motor, and the ones that do, may not always share the data. everyone's combo is different . Use some good break in oil .If your slugs are .025 in the hole, then a shim gasket wil give you a tad more compression and make it less likely to detonate due to the better quench. Most of the cams mentioned here will work fine for your application I bet

have fun

Doug

cmonson
12-01-2008, 09:40:48 PM
the vortecs in stock form will love a split pattern cam b/c of the lack of exhaust flow. With a port/polish/larger valves/bowl blend, the exhaust side flow of the vortecs is far less of an issue, thus the reason why my split isn't much at all.

If you are interested in the reed cams, contact Dennis at www.reedcams.com

He will give a good discount for all nasty members. He is extremely familiar with the vortecs and will cut a cam for you based on the information you provide.

That reed cam that I have has no problems with breaking loose in 2nd gear running 40MPH, it idles at 900 RPM, and has enough vacumn for stock power brakes.

Based on my combo, it was an excellent choice for me. Contact Dennis and see what you think...

RCJ
12-01-2008, 11:04:15 PM
I ran a comp xe260 in my 71 for about 20,000 miles. it had the world product heads the rest was about the same as your car even the the high gears.I' ve switch to the xe268 and 3.73 with an airgap intake.With open headers it will run in the high 12s

RockinZ
12-01-2008, 11:18:28 PM
Welcome to the forum RCJ! :)

How is the newer set-up on the street? what kind of TC do you have?

cmonson, that sound like a nice set-up!

hhott71
12-02-2008, 04:36:19 AM
Port entrance porting means nearly zero.
The Porting must be done around the valve guide boss (Teardrop shape it) and a Bowl clean-up along with the port entrance matching.

350 with flat top pistons (with 1,2,4 valve reliefs) and the stock 0.025" deck height and the proper Felpro 1094 (0.015") gasket or stock GM steel shim gasket will result in a 10-10.2:1 compression with the fuelie or Vortec heads (64cc chambers). You'd have to CC the heads to be sure. Vortec heads like less timing than fuelie heads.
38-44º timing on fuelie heads was common, the Vortecs with a better chamber and port swirl likes 34º or so timing.

The Crane Energized 284 (100072) Cam and lifter set ($120) .480" lift and 228º dur 112º LC works very well in a 10:1 motor on pump gas even 91 octane (93 prefered).

hardline_42
12-02-2008, 10:43:54 AM
the vortecs in stock form will love a split pattern cam b/c of the lack of exhaust flow. With a port/polish/larger valves/bowl blend, the exhaust side flow of the vortecs is far less of an issue, thus the reason why my split isn't much at all....
This is good advice and why I mentioned intake vs. exhaust flow ratio after the porting in my first post. Vortecs suffer from poor exhaust flow in stock form and benefit from the extra duration on the exhaust side. If you can have your heads tested on a flowbench to see what they flow, you can make a better cam selection.

RockinZ
12-02-2008, 09:21:53 PM
This is really turning out to be a very informative thread for choosing a streetable cam for ported vortecs.

I'm planning to have my heads checked out soon. I will be sure to provide the info.

Thanks for sharing your knowledge!

Kyle :bowtie:

RockinZ
12-02-2008, 09:57:28 PM
oops posted in wrong thread

Doug Jaynes
12-02-2008, 10:19:24 PM
pretty much all chevy heads had poor intake vs exhaust ratios up until the LS series. a good bowl blend job helps that quite a bit. flow testing is helpful but it wont tell you which cam will make more power like a dyno would. Certainly the current trend is to have a split duration camshaft, but Id bet some non split cams would do as well, maybe :' ) Its not a cut and dried science, there are too many variables .

RockinZ
12-07-2008, 09:40:49 AM
Here are some photos inside the exhaust ports. Looks like the bowl job described in this thread was done - less the valve guide boss.

The guy that sold me the heads was using a Crane PowerMax
H-300-2, CRN-114051. He was planning a full race motor.
Says the springs are 1.25 diameter, max lift .500.
I don't plan to do more to the heads.

I'm leaning towards a Crane PowerMax H-272-2 right now.

Any comments on this, or experience with the above cam?

Thanks, Kyle

http://i397.photobucket.com/albums/pp56/RockinZ/ExPortJob001.jpg

http://i397.photobucket.com/albums/pp56/RockinZ/ExPortJob006.jpg

camertom
12-07-2008, 10:01:59 AM
Those are pretty good close ups.

Very good and I'm not so sure anything down there looks blended. Looks pretty rough around the actual valve seat approach. I don't think they have been bowl blended at all. The tower is a huge restriction. It looks like just the opening has really been reworked which is pretty much valueless.

Thats my take from your vaery good shots.

RockinZ
12-07-2008, 10:37:51 AM
Those are pretty good close ups.

Thanks, I used the close up setting on the camera and then shone a flashlight into the exhaust port. Turned out pretty good!

RockinZ
12-07-2008, 10:46:36 AM
Looks pretty rough around the actual valve seat approach. I don't think they have been bowl blended at all. The tower is a huge restriction. It looks like just the opening has really been reworked which is pretty much valueless.

That pretty much keeps me in line with going with a split duration cam with substantially more exhaust duration. Which is what I have found in the Cams I have mentioned so far.

Thanks to all of you for your advice and info.:p

RockinZ
12-09-2008, 09:58:34 PM
I bought the sealed power version of those pistons. going with vortecs too. I think in the northern site it show the compression to be 9.8 to 1 jim

Jim, I'm curious, what cam are going to put in it?

RockinZ
12-12-2008, 07:28:18 PM
I decided to poll three cam manufacturers, Crane, Lunati and Comp.

Here are their recommendations:
Crane Z 113522
268/280 adv duration
218/230 @ 0.050 in. lift
459/486 lift
LSA 112
intake centerline 107
1800-5800 rpm

Comp XE268H-10
268/280 adv duration
224/230 @ 0.050 in. lift
477/480
LSA 110
ICL 106
1500-5500

Lunati Voodoo 60103
Adv-268/276
227/233
489/.504
110
106
1800-6200

I think that both Crane and Comp gave me the right cam.
By the way, I emailed both of them.

NOW get this. I called Lunati and the tech suggested the above cam - he never asked if I had modded my heads for lift. When I told him they were good for max .500 he said that it was ok?? :screwup: I have never heard of it being ok to even get close to the max.

Any comments?

pdq67
12-13-2008, 12:45:37 AM
Fwiw, stock big valve double hump heads tend to lay down at .515" or so lift.

And those pic's to me show stock ports??

Imho, UDHarold's VooDoo 268 is SOTA so go w/ it.

I just tried to pull up AMOTION in Canada and it didn't pull up????

pdq67

RockinZ
12-13-2008, 11:44:45 AM
Fwiw, stock big valve double hump heads tend to lay down at .515" or so lift.

And those pic's to me show stock ports??

Imho, UDHarold's VooDoo 268 is SOTA so go w/ it.


pdq67

The 268 is too big for my vortec heads, max .500 lift isn't it? the exhaust lift is .504. :confused:

The bowls are ported the guide bosses are not. It's hard to see in the photo but I pulled a valve and their is definitely work done there. I will see if I can get a photo.

RockinZ
12-13-2008, 07:09:25 PM
I removed an exhaust valve, have a look.

http://i397.photobucket.com/albums/pp56/RockinZ/exhaustbowl01.jpg

http://i397.photobucket.com/albums/pp56/RockinZ/exhaustbowl02.jpg

http://i397.photobucket.com/albums/pp56/RockinZ/exhaustbowl03.jpg

http://i397.photobucket.com/albums/pp56/RockinZ/exhaustbowl04.jpg

http://i397.photobucket.com/albums/pp56/RockinZ/exhaustbowl05.jpg

http://i397.photobucket.com/albums/pp56/RockinZ/exhaustbowl06.jpg

79CamaroZ28
12-13-2008, 11:57:19 PM
Looks about 1/2 done. I would take the heads back to whoever did them and tell them your not happy with what kinda port job they did. It really does look like they didnt know what they were doing... Just my .02 cents but my street car went 12.01 at 110... Good luck.. Nate

BTW, I hope thats just assembly lube or something on the face of the valve job in the head. looks like some crud or soot build up or something. would really affect the sealing of the valve. might wanna have the heads checked for leakdown...

RockinZ
12-14-2008, 12:05:02 AM
Hey Nate thanks for the .02. The heads where purchase on ebay. 400 bucks for the pair. Came as is. I will have them cleaned up before the build for sure.

pdq67
12-14-2008, 12:11:09 AM
Install a UDHarold SOTA VooDoo 268 and then do Rust's old "Ghetto-Grind" to the retainer bottoms to up your valve lift clearance!

Can't get much easier than that and I would just get my old cheap 1/4" B&D hand drill out and several cheap CHINESE stones and polish away, BUT NOT change any port shapes and go.

pdq67

docwilcar
12-14-2008, 03:16:23 PM
IN THE "BEST OF HOT ROD" VOLUME 11, HIGH PERFORMANCE CAMSHAFTS, HOT ROD TECHNICAL LIBRARY BOOK PUBLISHED IN 2000, THEY DID A CAMSHAFT TEST ON AN RHS BUILT 350 WITH WORLD PRODUCTS S/R HEADS, 1.94-1.50 8.8 CR. ONE OF THE CAMS THAT DID VERY WELL WAS THE THE COMP CAMS 275DEH CAM WITH 219-229 DUR. @ .050 .468-.488 LIFT ON A 110 LSA AND 106 ICL. THIS CAM MADE 338HP @ 5500, AND PULLED 14.5" OF VACUUM AT 750 RPM AND 16.5 AT 1000 RPM. YOUR HEADS WOULD PROBABLY GIVE SOME HIGHER HP NUMBERS THAN THE STOCK S/R HEADS. AS AN INTERESTING SIDE NOTE, THEY ALSO USED A COMP 282S SOLID LIFTER CAM-236-236 DURATION, .495 GROSS LIFT, .471 NET LIFT WITH THE .024 LASH, AND IT MADE ALMOST IDENTICAL NUMBERS AS THE 275 DEH WITH 335HP AT 5500 RPM BUT THE 282S MADE SLIGHTLY BETTER TORQUE FROM 2000 UP TO 5000 RPM. THE 282S MADE 13" of vacuum at 750, and 15" at 1000 rpm. ONE OF THE OTHER CAMS THEY USED IN THE CAM COMPARO WAS THE COMP 286 MAGNUM HYDRAULIC WITH 236-236 .490-.490 LIFT 110 LSA ON A 106 ICL AND THEY USED THIS CAM TO COMPARE ITS STREETABILITY TO THE 282S WHICH HAS ALMOST THE SAME SPECS. WHAT THEY FOUND WAS THAT THE 286 CAM IN THIS ENGINE WOULD HAVE BEEN A REAL BEAR TO DRIVE ON THE STREET WIHTOUT A 2500 STALL AND SOME STEEPER GEARS. THE 286 MADE 348 HP AT 5000 RPM BUT MADE ONLY 10.5" OF VACUUM AT 750 AND 13"@ 1000. THE 282S MADE BETTER POWER DOWN LOW WHCIH THE AUTHOR OF THE ARTICLE EXPLAINED WAS DUE TO THE 282S SLIGTLY LESS DURATION DUE TO ITS VALVE LASH (ALTHOUGH I WONDER WHAT THE POWER WOULD HAVE LOOKED LIKE HAD THEY LASHED IT AT .015 ). THIS IS ONE OF MANY COMMENTS BY CAMSHAFT EXPERTS THAT STATE THAT A SOLID LIFTER CAM WILL ACT SLIGHTLY SMALLER THAN A COMPARABLE HYDRAULIC CAM. IN THIS TEST IT SHOWS THAT THE 282S WAS THE BETTER CAM, MADE BETTER POWER THROUGH OUT THE RPM RANGE AND WOULD HAVE MUCH BETTER STREET MANNERS IN A PRETTY MUCH STOCK 350 WITH ONLY 8.8 CR. THE 275DEH WAS ALSO A GREAT HYDRAULIC CAM IF ONE NEEDS A SPLIT PATTERN CAMSHAFT. OF COURSE WITH BETTER HEADS THE TESTS WOULD HAVE REVEALED HIGHER HP FIGURES BUT IT GOES TO SHOW ONE WITH A PRETTY STOCK 350 THE POWER YOU CAN OBTAIN WITH SOME OLD SCHOOL CAMS. THE ABOVE MENTIONED BOOK MAY STILL BE AVAILABLE ON EBAY OR AMAZON AND HAS A LOT OF CAM TESTS ON SMALL BLOCK CHEVY ENGINES USING DIFFERENT CAMS, MOST OF WHICH ARE ON SOME OF THE OLD STYLE CRANE AND COMP CAMS BEFORE THE ONSLAUGHT OF THE FAST RAMP CAMS FROM THE MAJOR CAM MAKERS. ON A COUPLE OF THE TESTS THE OLDER CAMS MADE AS MUCH HP AS THE NEWER ONES ONLY AT A LOWER RPM WHICH IS GOOD FOR STREET CAMS. ANOTHER GOOD CAMSHAFT BOOK IS DAVID VIZARDS "HOW TO BUILD AND MODIFY CHEVROLET SMALL BLOCK V-8-CAMSHAFTS AND VALVETRAINS". ACTUALLY ANY BOOK ON THE SBC BY VIZARD IS WORTH READING AS THIS GUY KNOWS HOW TO MAKE SOME HP.

pdq67
12-14-2008, 05:55:00 PM
Lets do the cam and intake tests this way!

355 engine w/ 4-notch flat-tops and -186 heads w/ 66 cc chambers and big valves and shim headgaskets to hold the quench tight and to make right at a GOOD pump gas engine 10.25 to 1 CR.

A good old 300-36 against the new Weiand dual plane 300-36 replacement and an E-brock RPM Air Gap. A tuned 3310-2 and a cheap set of Summit 1.625" dia., 4-tube long headers!

Now test cams and intakes away!!

This is the sweet spot combination that will show just how good the old 268/270/272 hy-cams do and then look at the 278/280/282 solid lifter cams too...

pdq67

PS., and the old CC 246 PE and their 275 DE are very good cams!!

RockinZ
12-16-2008, 11:02:46 PM
I just ordered every David Vizard book I could find on Amazon.

I'm still flopping all over the place with a cam choice. I can't make a final decision and it's driving me nuts. :confused:

Important info to note. I measured my valve lift (more info in the Vortec Thread). I have a generous amount of lift. I measures about .750.
You can see how low that valve seal is sitting, it's been machined way down.
http://i397.photobucket.com/albums/pp56/RockinZ/valveguide001.jpg

Right now I'm just wondering if the springs that are on there are ok. they are new and were meant for a Crane PowerMax 114051: 300/308, 238,246@.050, Lift .480/.495.

So, I'm not limited by lift, and I can incease my compression with a .015 head gasket to over 10 to 1.

I want the car to keep its' manners on the street. So far I have some great advice from some of you. Now that the specs have changed a bit, I would really like hear some opinions.

Thanks Kyle

RockinZ
12-21-2008, 10:22:30 AM
I spent lots of time researching the cam for my engine. I thought for sure I would find something different from what most recommend. but, No!
It's going to be the XE268H.

My engine should be running around 9.75 - 10 to 1 static compression with my .039 head gasket. The variation is I don't know how big my vortec combustion chambers really are (62-64cc). This gives me a Dynamic compression range of 8.1-8.3. to 1, which is ideal.

I could have gone with a bigger cam amd higher compression with a thinner gasket .015 shim. but that moves the power up the rpm range into a place I would hardly ever see on the street. I want to see that low end launching power!

Desktop Dyno: 421 TQ @ 3500, 380 HP @ 5000 :bowtie:

pdq67
12-21-2008, 12:06:32 PM
Go w/ Harold's SOTA VooDoo 268 and never look back!

pdq67

RockinZ
12-21-2008, 01:57:20 PM
Go w/ Harold's SOTA VooDoo 268 and never look back!

pdq67
I saw you post and redid my calculations - I must have made a mistake. They both seem evenly matched. Voodoo slightly higher torque, a little less HP, but nothing huge. Now I'm undecided again :confused:

pdq67
12-21-2008, 03:28:45 PM
IMHO, you CAN'T go wrong w/ a UDHarold cam so install the VooDoo 268!

pdq67

RockinZ
12-21-2008, 04:01:29 PM
IMHO, you CAN'T go wrong w/ a UDHarold cam so install the VooDoo 268!

pdq67


Any reason why for my set-up? They both seem pretty evenly matched. Other than Voodoo being a cool name ;)

pdq67
12-21-2008, 06:53:42 PM
Sure,

Harold make's his cams to be easier on the closing side so the valve train take's less of a beating.

Call Harold here..

(662) 562-4933

and ask him and if you do, please say hello from ol' pdq67 for me!

pdq67

RockinZ
12-23-2008, 12:12:29 AM
All right, I'm putting it up to a vote!

RockinZ
12-23-2008, 08:55:21 PM
Only two votes so far... any more?

RockinZ
12-23-2008, 09:48:56 PM
But didn't he also design the XE cams at Comp?

RockinZ
12-23-2008, 11:19:24 PM
I just read up on it at chevelles.com, Harold designed the HE line, not the XE.

Led Zep
12-24-2008, 10:48:43 AM
"A heavy vehicle will accelerate faster if torque output is increased by 10 ft-lbs at 2000 RPM,rather than adding 10 HP at 5000 RPM" David Vizard.Go with the Comp XE 268.I have ran both cams,the comp outperformed it.My car ran 103 MPH in the quarter vs. 101 MPH with the voo doo cam.It will outperform it on DD 2000 as well.This is a big deal,be sure to Advance the cam +4 degrees when you install it,you can tell the difference.

grog
12-24-2008, 12:20:46 PM
Isn't the cam ground 4 degrees advanced? Check it before advancing any further.

Don't worry about a 110 degree cam on the street. If you have fuel injection, the computers like the wider separation but you're using a carb.

Led Zep
12-24-2008, 07:33:32 PM
[QUOTE=grog]Isn't the cam ground 4 degrees advanced? Check it before advancing any further.

Alot of cam companies do that.But when I degreed my cam, it was less than a 1/2 degree retarded in the +4 position on my sprocket.I went ahead and bolted in that way rather than drilling a new hole.

docwilcar
12-24-2008, 08:23:06 PM
Food for thought. I am sure that in your readings of Vizard you see that he is a very big fan of tight lobe separations on the small block chevy. I would look at a cam on a 108 lsa for your motor. Something close to the 268HE would be the Isky 270 Mega cam at 221-221-.465 lift 108 lsa. Vizard made some pretty decent hp with a Comp 270 cam ground on a 108 lsa, 345 hp as I recall with some pocket ported 882 heads.

Led Zep
12-24-2008, 08:57:18 PM
The comp cam is a smaller cam out performed the larger Voo doo cam.I ran both cams,and give first hand account. For the record,just want the best cam for the money.

pdq67
12-24-2008, 10:27:17 PM
Please call Harold up (662) 562-4933 and ask him point blank if what Led Zep say's is true?? He will explain all this to you in a NY minute and be glad to!

And I would want your engine IF it was mine to be right at 10 to 1 CR'd w/ either .015" or .020" thick shim headgaskets.

I'm cheap so I use the .020" thick jobbers in ALL my engines!

I will post it again AND probably get bit at for doing so, but Harold created this smaller BB solid lifter cam for me that is spec'd;

278/249/161, 110/106, .618" gross lift and need's .018" lash on both sides b/c I flat won't run a solid street roller like I wanted to in CC's great old 288AR.

Take the time to check the spec's between Harold's solid lifter cam and CC's great old 288AR solid street roller!! Harold said his flat tappet will match it and may even beat the 288AR by a schosh! You talk about SOTA cam design straight from the horse's mouth!

pdq67

RockinZ
12-24-2008, 11:46:12 PM
This is my problem, to get to 10 to 1 I need to use a .039 gasket and go to high on quench. I have a .039 ready to go, already bought it with a short block kit. but now I'm concerned about quench. what do I do? go to dished pistons?

I'm trying to keep costs down to a minimum without compromising too much.

confused

pdq67
12-25-2008, 12:58:24 AM
Look, I've went back and forth through this a couple of time's and unless I have missed something, at .030" over and a DITH 350 of .025" stock w/ 64 cc heads, you should be right at 10.25 to 1 CR'd or so if you are using the thin shims!

62 cc heads, then recalculate and go w/ each shim thickness is all so you will know for sure, imho...

pdq67.

PS., and guy's, please come back ans set me straight!

RockinZ
12-25-2008, 08:34:47 AM
Look, I've went back and forth through this a couple of time's and unless I have missed something, at .030" over and a DITH 350 of .025" stock w/ 64 cc heads, you should be right at 10.25 to 1 CR'd or so if you are using the thin shims!

62 cc heads, then recalculate and go w/ each shim thickness is all so you will know for sure, imho...

pdq67.

PS., and guy's, please come back ans set me straight!

Sorry pdq67 I don't mean to be a PITA but... I tried two calculators and came up with 10.4 to 1 for the spec above. Add the smaller chambers and it's 10.64. Way too much DCR for the 60 ADV intake closing that both the Voodoo and the XE 268s have.

Led Zep
12-25-2008, 09:15:17 AM
pdq67,trust me,I was mystified(and pissed,lol) why my car slowed down in the quarter.Could not figure it out,until running the numbers on DD2000.What became apparent is the Voo Doo 268 does make more HP(8 more HP)but the XE268 makes more torque,epsecially overall.Average torque curve from 2000 RPM to 4500 RPM for the VD 268 was 374 ft-lbs.The XE 268 was 387 ft-lbs.BTW my combo is flat top 355 with unported vortecs with bee hive springs.

RockinZ
12-25-2008, 09:33:58 AM
Led Zep, what's your quench height and compression?

RockinZ
12-25-2008, 10:01:21 AM
Food for thought. I am sure that in your readings of Vizard you see that he is a very big fan of tight lobe separations on the small block chevy. I would look at a cam on a 108 lsa for your motor. Something close to the 268HE would be the Isky 270 Mega cam at 221-221-.465 lift 108 lsa. Vizard made some pretty decent hp with a Comp 270 cam ground on a 108 lsa, 345 hp as I recall with some pocket ported 882 heads.

docwilcar, I didn't get the Vizard books yet. What you saying is makes sense, if I look for a 108 instead of 110, I should get the DCR under control. I will look into it, thanks for the insight. ;)

Led Zep
12-25-2008, 10:34:08 AM
Led Zep, what's your quench height and compression?

I do not know,I did not check it.I am guessing around 10:1.I run 93 octane and my engine has survived the last 8 years,including over 200 passes at the strip.I use Fel Pro Blue permatorque headgasket,nothing fancy.If you have a desktop dyno,play with the numbers with cam selection.You stated .500 max lift for your spring,may want to try a smaller cam with 1.6 rockers,might suprise you.For the record,I am not advocating a particular BRAND of cam,just relating my personal experience.With the DD,pay close attention to the torque numbers,you will see peak HP is not enough to overcome the broader torque curve,on a pump gas engine,IMO.

pdq67
12-25-2008, 04:34:37 PM
Please call Harold here (662) 562-4933 and flat ask him if the XE268 will out power his VooDoo 268?

And tell him ol' pdq67 told you to call him.

pdq67

-=79z28=-
12-25-2008, 04:47:36 PM
RockinZ, use this compression calculator so we can be on the same page, many here have used this:

http://cochise.uia.net/pkelley2/DynamicCR.html

* first read it, then at the bottom, download it (the one with VB6 files) and go!

you can also check your DCR with it (DCR is important to get an idea of where you stand as far as pump gas use is concerned)

next, you want a quench between .035-.040, the higher compression with this doesnt mean it will be more apt to detonate, the tighter quench will help fight off detonation. so basically, you want to use a .015 shim head gasket (as long as you know you've got a stock deck height motor)

lastly, listen to pdq67! LOL (you know i got your back dude)

bfmgoalie
12-25-2008, 07:09:51 PM
docwilcar, I didn't get the Vizard books yet. What you saying is makes sense, if I look for a 108 instead of 110, I should get the DCR under control. I will look into it, thanks for the insight. ;)

Hey RockinZ, its I love it and I need it, I bleed it........ I love Deep Purple. But why not Trampled under Foot by Led Zepp. That's a car tune...well, almost.

The Biker 69

RockinZ
12-25-2008, 07:50:15 PM
RockinZ, use this compression calculator so we can be on the same page, many here have used this:

http://cochise.uia.net/pkelley2/DynamicCR.html

* first read it, then at the bottom, download it (the one with VB6 files) and go!

you can also check your DCR with it (DCR is important to get an idea of where you stand as far as pump gas use is concerned)

next, you want a quench between .035-.040, the higher compression with this doesnt mean it will be more apt to detonate, the tighter quench will help fight off detonation. so basically, you want to use a .015 shim head gasket (as long as you know you've got a stock deck height motor)

lastly, listen to pdq67! LOL (you know i got your back dude)


Guys, I don't want to run us around in circles here, but that is one of the calculators I used. here is a screen grab. Are my numbers right?
http://i397.photobucket.com/albums/pp56/RockinZ/PatKellyCompressioncalculation.jpg

RockinZ
12-25-2008, 07:54:41 PM
Hey RockinZ, its I love it and I need it, I bleed it........ I love Deep Purple. But why not Trampled under Foot by Led Zepp. That's a car tune...well, almost.

The Biker 69


Thanks bmfgoalie! ;)

-=79z28=-
12-25-2008, 08:33:07 PM
ok, your DCR is 8.75:1. a little high, but the quench and vortecs can do that easy on 93.

also, just wondering how sure you are that your heads ARE in fact 62cc.

if they are 64cc, your lookin at 10.3:1 static and 8.5:1 DCR

according to camquest 6 (available for download at comp cams site) shows 390 hp @ 5000 and 438 tq @ 2500

sorry id this stuff has come up before, i just got into this thread. LOL

RockinZ
12-25-2008, 09:09:23 PM
The heads a for sure shaved so not 64cc, and many have said when they cc'd vortecs that they have come up with 63 or 62cc. I have to go with the higher compression possibility and base my choice on that.

pdq67
12-25-2008, 09:41:51 PM
Thanks -=79 for the back up!

You know, I was just thinking about what a good old BUT ground modern Crane 274H06 say like this..

274/224, 106/102, and a low lift to hold valve train hammering to a min. of like just .460" lift on both sides.

274 to drop DCR down a schosh and the 106/102 to really kick up the midrange is all. And if .460" lift isn't enough, then install 1.6 ratio rockers.

pdq67

RockinZ
12-25-2008, 10:08:43 PM
pdq67 I will look into that cam, but that lsa shouldn't have much vacuum.

Speaking of Crane, I was looking at the Crane Powermax H-272 2. The Intake closes at 67 ABDC. 272/284 adv dur. 454/480 lift and has 112 lCA. 1800-5600 rpm range.
Dynamic CR will be between 8.1 - 8.3.
DD with a 10.5 CR gives me 378 tq @ 2000 rpm, 420 tq @4000 rpm, 396 max HP @ 5000rpm.

I like those numbers and I should still have brakes.

What do you guys think?

RockinZ
12-28-2008, 06:19:55 PM
I'm going with a Crane Energizer 278 H10 (pn 100132).
As I looked further into what quench was all about I realized I could be in more trouble without that good quench height.
So I calculated a range of 10.35 to 10.6 static Compression
And a 8.05 to 8.25 dynamic compression with this cam. Should keep me safely out of the detonation Zone.

Thanks to all of you for you suggestions and advice.

ANd come spring I will be filling up at Petro Canada for their 94 octane! :crazy:

RockinZ
08-21-2009, 09:13:31 AM
It seems I am spending more time with my car at the track than anywhere else. This is why undercamming my engine is so obvious. When I built it I did not realize I would be running it down the track every week or two.

After reading more on this (Vizard) and being told my cam is only good for a taxi, and having detonation issues on a hot humid day even running 94, I realized I screwed up on my cam choice. my apologies to pdq67 and others who were trying to get me to see the light.

http://image.popularhotrodding.com/f/8774858+w750+st0/0607phr_11_z+camshaft_basics+lobe_centerline_angle_determination_chart.jpg

My cam's overlap of 58 is not enough. On top of that, according to Vizards chart above, my lsa should be 107, as docwilcar was trying to tell me. Probably a comp 286 AH-8 is the ticket, but I will need more stall, mine's 2600-2800. So this is not in the near future for me.

Well, maybe I can replace my crappy GM stamped rockers and balls with some 1.6 ratio roller rockers. Maybe this could help?

sooner
08-21-2009, 08:23:32 PM
I still think that an xe268 is your best choice, but if you need more than 58* of overlap its not going to work for you.

In an off the shelf grind, I would think that a 280 megacam, maybe with a 1.6 rocker on the exhaust side would be an excellent choice. It would give you more overlap and the 108* lsa you desire. Not to mention, its one of the best sounding cams of all time Imo. just my .02

RockinZ
08-21-2009, 11:46:00 PM
I still think that an xe268 is your best choice, but if you need more than 58* of overlap its not going to work for you.

In an off the shelf grind, I would think that a 280 megacam, maybe with a 1.6 rocker on the exhaust side would be an excellent choice. It would give you more overlap and the 108* lsa you desire. Not to mention, its one of the best sounding cams of all time Imo. just my .02

That xe268 would make a bottom end torque beast, but I would loose on the top.
I will try to DD that Isky cam and see what happens.

Thanks

RockinZ
08-22-2009, 12:06:18 AM
Jay,

I like your choice of the Isky cam. Very similar to the comp 286 AH-8 which to me, is what I should have installed. 236/244, 286/292, 490 lift, 108 lsa

sooner
08-22-2009, 04:15:33 AM
howards cams also sells a dirt cheap cam and lifter kit that specs out at 288/288 (232/232) .480/.480 on a 108* lobe center for $115

RockinZ
08-22-2009, 10:54:58 AM
Well, I redid the math the 280AH-8 oval track cam is an even better match for my stock bottom end rpm range.

Now I just have to find the cash....

sooner
08-22-2009, 01:14:03 PM
That 280 ah-8 looks like a great choice to me. Here is a link to that cam for the others that might want to take a look.

http://compcams.com/Cam_Specs/CamDetails.aspx?csid=142&sb=1

Have you started looking for a converter yet?

RockinZ
08-22-2009, 05:13:36 PM
That 280 ah-8 looks like a great choice to me. Here is a link to that cam for the others that might want to take a look.

http://compcams.com/Cam_Specs/CamDetails.aspx?csid=142&sb=1

Have you started looking for a converter yet?

My 2800 stall will have to do for now.

ProStreet383
08-23-2009, 12:32:17 PM
Lunati hands down. Comp cams blow goats IMO.


Here is the 60104 in our nova. This cam absolutely RIPS!


http://www.youtube.com/watch?v=W9AmbTx1W0k

old blue 75
08-23-2009, 10:33:44 PM
Here is where you need to go to get the correct cam IMHO.


http://motortecmagazine.com/mainpage.html