View Full Version : which cam to get
12-29-2004, 04:20:00 PM
okay guys ive got a 350 in my camaro. the engine has headers and true dual exhaust. also it now has a weiand 7546 manifold, which i could swap out for a eddy perfomer which i also have (which one would work better?), and it has an eddy 600 carb. the car has a th-350 and 3.42 posi in the rear. I want to get some take off power so i can snap my head back when i take off, and i plan to put a cam in soon, but i am lost when it comes to this. please help me out guys, i am 17 years old and new to all of this, i restored the car myself, now i want to start learning about the engine part of it. so all information is appreciated. also i was thinkin bout swappin the rear end gears out for some 3.73s or 4.10s...think that would help?
Thanks a lot,
12-29-2004, 04:23:00 PM
also guys i forgot to mention, i picked up a speed pro cam that has dur. @.050 280/280 im not reall sure about what this means but if it would work let me know, but if not, let me know too!!! thanks guys!
12-29-2004, 04:52:00 PM
If that cam has 280/280 duartion@50, that is a HUGE cam. Something that big is not going to work with your curent setup. Personally if your running the stock heads, I wouldnt go with anything bigger than 230@50 dur.
just my .02
And if this is also gonna be a daily driver go with the 3.73's.
[This message has been edited by CamaroMan79 (edited December 29, 2004).]
12-29-2004, 05:27:00 PM
I like the 7546 manifold, but if its a stock converter you may want the performer i dont think there is a big performance difference from one to the other even though they are completely different designs
if your gonna drive on the interstate id leave the 3.42's if your only driving 55 go 3.73
what torque converter do you have, or what RPM does it stall at?
[This message has been edited by Mwilson (edited December 29, 2004).]
12-29-2004, 05:59:00 PM
i have a stock converter, thanx for all the help keep it comin guys!
12-29-2004, 06:07:00 PM
Part # 112431
Ask these people
12-29-2004, 06:18:00 PM
If that cam is really a 280/280 @.050 cam then that thing is HUGE, personally WAY to big for the street. However if that's advertised duration (seat to seat), you might be alright. But you need to clarify what it is.
I can't really help you until you let me know what stall speed your torque converter is, and you need to decide which rear gear you're going to use.
Personally with a TH350 I'd stay with the 3.42's. But if you want to upgrade, the 3.73's are possible on the street. Our 79 Z has 3.73's in it and it runs between 3800 and 4000 RPM at 65 mph on the highway. However, if you're concerned about gas milage, forget the 3.73's and stick with the 3.42's.
Give me some more info and I'll let you know more.
12-30-2004, 01:57:00 AM
Engine parts must work together as a package, same goes for the rest of the car setup.
It's really hard to do it part by part and get it right. You may lose some power now, but down the road when you can change heads you could gain alot more. Gain more now but when you change another part later lose some power, etc etc
For a good street/strip car that sees alot of street driving stick with 3.42 rear gears. I'm running 3.42 gears in my 88 camaro, 355 engine, 2800 stall. I get around 13-14 mpg and run 0-60 mph in 4.2-4.6 sec, 1/4 mile in the 12's with the trap speed to go 11's if I could get it too hook.
It's really hard to tell you what cam to use based on the info you gave. To build a great performing engine you need info on heads you have now, heads you will change too ater if thats the case, compression ratio, etc etc.
You will need/want a dual pattern cam for best performance (more duration and lift on the exhaust side than the intake)
(duration is the amount of time it holds the valves open) (lift is the amount it opens the valves)
As a very rough gen. guide line I would say run a dual patt. cam in the range of 260 to 280* (10* or so more on ex. side like a 268/278)
These # are advertised duration.
With a bigger cam, it means high lift, and that means you will more than likly need new stronger valve springs. Get springs that match up with the cam
2200-2600 rpm stall converter if drove alot, 2600-2800 stall if you can live with alittle less fuel mileage
I would also rec. the edelbrock performer intake.
Read up and learn as much about timing, and carb tuning as you can. If you aint got into setting up the timing curve, and dailing in the carb, you'll be shocked as to how much power your throwing away.
Set timing to 36-38* total w/o vac advance hooked up, change springs in dist. to get the curve starting at about 800 rpm, and fully advanced by 2800 or so rpm for your engine (stock dont fully advance till 3600-4500 rpm)
learn how to read spark plugs and let them tell you how to tune the carb. Buy the $50 cal kit for the carb, and change the metering rods, jets, setp up springs going by seat of pants feel, plug readings, and speed (best done at a drag strip)
What about your spark plugs?? What kind and number are you useing.. You shouldnt need a colder plug cause it sounds like you have stock pistons/compression. depending on heads run an AC delco R45TS or R45S (if you have the old washer seat plug heads pre 1973 I think), or a NGK V power plug that crosses to the R45
12-30-2004, 08:02:00 AM
The cam i recommended was a dual pattern and it was based on him telling me he has a stock converter
What are the numbers on the end of that cam you have?
13.23 @ 102 and dropping
believe it or not no nitrous or blower!
[This message has been edited by Mwilson (edited December 30, 2004).]
12-30-2004, 09:26:00 AM
I'm going to bet that is .005 duration / advertised. Have never even seen a hydraulic with that much 0.050",, them there is solid lifter / roller numbers. Even then,,, 280° seat to seat is going to be a LOT for a basically stock motor (heads and compression) I'm going to be even more conservative than most and say you should keep 0.050 duration under 220° until you have better heads and compression.
Probably the single most thing that will wake the car up and bring on tire frying traction problems is a 2400-2800 stall convertor. That stock convertor is going to kill any standing start acceleration with all but the mildest of cams.
12-31-2004, 12:22:00 AM
Mwilson would you please post the cam spec's when you mention the Howards link, only b/c it's just a hassle ta go over to their site each time and check them is all.
Bttt, and heck, no more then a good old CC 268HE or Crane/Cam Dynamics 272/272 Energizer and the mentioned Performer will do a good street 350 motor nicely, imho...
12-31-2004, 08:06:00 AM
Ops that wasn't a dual patern,
Man ive tried a bunch of cams for now the one i have is the fastest i have tried some simular to the couple you sugested and they were considerably slower in my car im sure there is a cam out there that would make me think the one i have now is slow! This is the first Howard cam ive tried so who knows maybe they got lucky when they recommended it? I bet the 268 or 272 would be good in his car with that converter
[This message has been edited by Mwilson (edited December 31, 2004).]
12-31-2004, 02:03:00 PM
<font face="Arial,Verdana" size="2">CC 268HE or Crane/Cam Dynamics 272/272</font>
Those are great entry level cams and I have ran both and still have the Cam dynamics 272 in my 327 now since 82 or 83.I ran the first design 268 when it was a 108 LS and that cam ran fantastic.
1978 Z-28 purchased new by me -$6750
Click here (http://f1.pg.photos.yahoo.com/ph/someonehasthisid/detail?.dir=/d752&.dnm=aefd.jpg) to view present state photo
Look above for glory days.
1982 350 S-10
[This message has been edited by Mike-78 Z-28 (edited December 31, 2004).]
01-04-2005, 03:09:00 AM
I ran a comp 284 duration 480 lift in my 79 rally sport in a stock 350 backed with a 2800 stall and 2:73 gears and headers and i must say i was impressed with the way it performed.Just dont go to big like i did this time i think i over did(thats a big understatement lol )i just built a 355 and stuck in a crane cam with a 296 duration 539/588 hydraulic roller.It performs good when i'm not breaking stuff on the car since it cost me my passenger's side exhaust and gas tank when i literally twisted the drive shaft right at the yoke snapped the universal joint into pieces. But thats the price ya pay for wanting to go fast
01-04-2005, 03:27:00 AM
i ran the 284 480 on a dish piston 350 once and it ran 8.30's in the 1/8 then when i built a flat top motor i kept that cam and the flat top motor ran the same time until i went with a bigger cam?
01-04-2005, 05:29:00 AM
might he be talking about 280 degrees advertised duration? isnt that like 130 actual or somethen?
i dont know i got this crane cams Energizer 278H spose to have fair idel, and make power to 5600 rpm, or was it 6500 rpm?
01-04-2005, 04:07:00 PM
The Performer RPM is really an overlooked cam. I'm going to replace my XE with one and see if I like it as much as some of the folks I've talked to.
01-04-2005, 04:49:00 PM
Yeah but would you want the Performer RPM cam with the Performer intake manifold?
Im currently looking into a cam myself and have the eddy 600cfm carb and eddy performer intake. All of this in a 350 motor.
01-04-2005, 05:14:00 PM
If your motor currently has the stock cam and heads with the 7546 (single plane intake) and headers/duals then you've got a bit of a mismatch on your hands right now. High RPM intake with a low RPM cam and heads. You don't want to create an even worse mismatch by shoving in too big a cam....
As was said by others, above, the COMBINATION of parts is everything. No single part makes the motor perform.
Here are, in my humble opinion, the 3 things you MUST match correctly if you ever want to get your money's worth:
Everything else is almost trivia beyond that. You can go too big with the carb or too small with the exhaust and it'll still make decent power. But if you get just one of these things mismatched, it'll be a dog.
You say you are sticking with your current heads for now, and obviously, you can't change the compression without swapping heads or tearing the motor down to install different pistons. So those 2 things are what you have to work within when choosing a well matched cam. What are we starting with??
I'll take a few guesses, maybe you can fill in the blanks a little. I assume this is the original engine from 1976 or a similar stock replacement motor out of a junkyard or a rebuilt replacement motor.
1. Heads- probably cast iron 76cc "smogger" era heads with smallish 1.94/1.50 valves. It would be best if you could yank the valve covers and get the casting number off of them (make sure both heads are the same casting!) and then we wouldn't have to guess any more.
2. Cam- We'll assume it's really a "stock" cam and that means REALLY small. Probably well under 200* duration @ .050 and not much lift (under .400").
3. Compression- with the heads I described above and stock dished-style 350 pistons used in MANY stock/replacement 350 engines your compression will probably be well under 9:1 (probably more like 8.2-8.5:1)
The heads don't flow very well and the compression is very low. How do you cam for a motor like that? You stay conservative and get something that's going to work from about 1500-5000 RPMs. If you go too big you'll kill your cylinder pressure and the motor will be a PIG down low in the RPM range. You'll never make up on the top end what you give up down low. With a stock converter that will only allow your motor to spin up to about 1800 RPMs coming off the line it would be misery driving it with too big a cam.
Cam recommendation #1 (biggest I would put in): Summit K1103. 214* intake duration, 224* exhaust (@050). Lift of .442/.465". 112* lobe separation angle.
Cam recommendation #2 (little more conservative): Summit K1102. 204/214* @ .050. Lift .420/.442" 112* lobe separation angle.
You can buy a complete kit with lifters for only $80 and they are good cams, especially for what you are trying to do. Also, they will work with stock heads (especially the K1102 cam) in most cases without having to machine the heads for clearance to take a higher lift cam. That's an important consideration since having the heads machined for higher lift would require taking them off the engine, which is more work and money.
You will need to upgrade the valve springs since your stock ones won't adequately control a more aggressive cam (ANY cam other than stock), especially over 5000 RPMs. This is NOT optional. Unless you never want to make any meaningful power over 4500-5000 with your new cam you need better springs. Almost all stock SBC heads will take a set of Crane 99848 springs. They are literally drop-in replacements for stock, requiring no head machining and they have considerably more pressure than stock springs (especially if your stock springs are decades old with tens of thousands of miles on them). YES, you can install them with the heads still on the motor. Ask how in another thread if you don't know how and many people will be glad to help you out (including me).
Last thing I'd do is swap the current single plane out for the Edlebrock Performer. Single planes look cool as all get-out but they aren't what you want on this motor. From 1500-5000 you want the better torque the Edelbrock dual plane will give you in that RPM range.
Then it's a matter of tuning. Spark advance, carb jetting, etc. to get all the torque and HP out of the combo that you paid for. Don't overlook this. You can be leaving a LOT of power on the table with a less-than-optimal tune. Differences you can feel in the seat of your pants. Again, ask around on the board and many people will be glad to offer pointers.
That's about as good as I could offer you to "optimize" what you've got with what you're trying to do and the partsyou are looking to upgrade. I've done MANY upgrades like this for friends and for myself. This is real-world stuff I've found actually works.
Well, if you read this far you probably want to know how much power this thing is likely to make, right? OK. Peak HP about 275-285 (@ flywheel) between 4500-5000 RPMs. Peak torque about 350-375 ft/lbs around 3500 RPMs.
01-04-2005, 05:24:00 PM
By the way, you might be interested in the Camaro in my signature. The engine in it is not all that different from what I spec'ed out for you, above. It't got a little more compression (9:1) and considerably better flowing heads (Dart Iron Eagles) but is otherwise almost dead-on the combination you are considering building (even the cam is very similar to what I recommended for you). Edlebrock Performer intake, 600 CFM Holley vac sec carb, small tube headers, etc. Even with the stock 2.73 gears and stock stall converter in it the car ran 13.6 @ 104.5
I figure it makes about 320-330HP at the flywheel. Your motor with lower compression and stock heads will be down about 40-50HP from my combo, probably, but that should still be good enough to get you some solid 14 second timeslips in the high 90 MPH range, even in a 2nd gen Camaro which weighs more than my 3rd gen.
92 Camaro RS. Out with the old 195K mile 305 TBI motor, in with a super mild low-buck carbureted 350 built entirely from spare parts I had laying around the joint. 13.5 @ 104 on a biffed run with the new 4.10 gears. If knew how to drive it would run 13.3 or better. Still using the worn-out original 200K mile tranny and stock stall converter.
78 Malibu. Inherited from my Grandomther with only 35K on the odo! 13.4 @ 107 with mild N/A 383. With Weiand 142 blower installed....... not quite so mild. Orignially shooting for 11.99 on street tires, but mid 12s appears to be the best it's gonna do. Too much cam, not enough converter and nowhere near enough traction.
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