Got some parts from some 72 Camaros in a boneyard, and they also had a nice 64 SUburban body and chassis with a blown up V6... I'd like to buy it, really really nice styling, and I love Suburbans, but don't have the time/money/room for it at the moment. I think my mom or dad might also try to buy it since I probably won't...
So I have been toying with the idea of when my 230,000 mile 89 Suburban goes (should last 120,000 more I bet), how great it would be to get a 62-66 GMC Suburban or maybe chevy.

Alright, I was thinking to take the modern disc/drum power brakes, power steering, and maybe even tbi off of my suburban when it is kaput, or a donor vehicle in the boneyards, and getting an old burban like that and upgrading it to be a little more modern.

I have 307 in my former SS396 that will be forgone to a 406 sbc soon. I was thinking about engine combos for something that will get good mileage and still have some power if I were to ever build such a truck. Suburbans are such great haulers, it's my only daily driver (89 350 TBI 200R4 2WD).

I doubt I could equip the GMC 305 big block 6 cyl. with any kind of TBI, or vortec heads for that matter, so I was thinking about possible engine combos.
sbc's:
283 = 3.875" x 3.00"
302 = 4.000" x 3.00"
305 = 3.740" x 3.48"
307 = 3.875" x 3.25"
327 = 4.000" x 3.25"
350 = 4.000" x 3.48"

So I was wondering what crank and rods I could throw in a 307 block to get a longer stroke out of it for more torque? I would be limited to either 283 or 307 piston compression heights unless I could find some other odd sized rods to make up the difference, like a 5.565" from the 400, some of the newer generation rods, etc.

What would it take to do a 307 block with a 305 or 350 crank? I wonder what the cheapest set of custom pistons I could made for this compression height up would cost? I'd have to buy pistons anyway if I was rebuilding another engine, plus I'd have to get the block and crank in another build anyhow. The long stroke is what I'd be after, and I even thought about just doing up a nice 305, except I really would want to use vortec heads and I think the bore on a 305 is too small. a 350 is 4.00 stock, and I'd be at about 3.905 at .030 over on a 307 block. I think the .0475" less clearance between the 307 +.030" vs the 4.00" 350 wouldn't make much difference.

If I could get the right length rods or custom pistons, I'd be looking at about 334 cid, which would be really nice for what I'm looking for. nice running TBI, medium displacement and long stroke so I could still pull trailers, probably a 5 speed for the extra towing punch. That'd make a real nice truck.

Can someone tell me what compression height pistons I'd need, or what length rods with a 283 or 307 piston?????

Anyhow, I'd like to know what I'd be looking at here with the crank swap, as I'd have most of these parts, or be able to get most out of junkyards.
Also, the compatibility of a vortec in that bore size.

Thanks!


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'71 RS/SS pile of parts: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / 12"/11.1" 4 whl discs / big sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

[This message has been edited by Chuck78 (edited August 08, 2005).]

Here is how you do this..

a SB deck height is 9.025".

you have three rods to choose from other then custom length ones. 5.565" (400 motor), 5.7" all other SB's and 5.94" powder rod (later baby 265 LT-1 motor).

9.025" minus 5.7" for a standard rod then minus 1/2 your stroke, and from what's left, take away the standard .025" piston, down-in-the-hole and that is your compression distance from the center of the wrist pin to the deck of the piston!

Hope you have fun playing around.

And at work I have a big table I found somewhere on the web that lists a whole bunch of stuff like this that is done to various motors!

I bet if you look over at some "Roundy-Round" motor site's, you may be able to come up with just what you need??

I say this b/c they have all sorts of weird motor size limits and such...

[This message has been edited by pdq67 (edited August 08, 2005).]

For the money you'd tie up in custom pistons, crank machining, etc to build a funky engine, I think you'd be better off heading down to the local wreaker for a complete take out 5.7L from the early to mid 90's pickup, or possibly a later 90's vortec setup, either way I'd do it complete with factory computer and such, no better combo for power and mileage, especially with an overdrive trans.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

yeah, that might be an alternative, but it'd be interesting to have something fairly unique out of what I already have. If I could find a set of pistons for the right compression height, I'd be pretty set for a fairly decent price. I'll see what I can dig up.


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'71 RS/SS pile of parts: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / 12"/11.1" 4 whl discs / big sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction


[This message has been edited by Chuck78 (edited August 09, 2005).]

You're making this harder than it has to be. Lots of people have put Vortec heads on a 305 successfully. They work just fine with the stock 1.94/1.50 valves.

Grab a junker 305 long block (practially free), rebuild with your choice of mild RV cam, put in flattop pistons, mill the Vortecs down slightly to 58cc (many report they are 62cc out of the box which means it doesn't take much milling to get this accomplished) and you'll be about 9.25:1 compression, which will work fine with a mild cam. Then drive it till it drops (which should be a long long time).

Sounds like a good plan. It would be nice if I could find some pistons for that compression height and the 307 bore, but not worth spending $400 or more for a set.


Now with what I just heard about gas prices today - no price drop in sight, and cost me $75 top fill up my 6 cyl 32 gallon work van, I think a 305 might be more in order, definitely leaning away from the 350...

EDIT:
Silvolite makes 6 pistons in the compression height I would need, if I shaved the deck down .004" from 9.025" to 9.021". The only funky aspect is, the 5.7 chevy rods use a .9272 (or is it .9273"?) piston pin. All of these pistons that would be the proper compression height in a useable overbore size use a .931" pin.

I would assume that most any machine shop could do the machine work to my rods to bore them out .0037" to use the larger pin that these pistons come with, and that would be no problem at all, correct? No other issues to be dealt with?

Also, I am slightly confused as to the compression height and deck height info. SBC deck height is 9.025". So I subtract half the stroke (3.48/2=1.74), subtract 5.7" for the rod, and then the .025 you say for piston down in the hole, is this meaning that a block that is zero decked no longer has 9.025" deck height, but rather 9.000" and this is what zero deck on a sbc means? Or is a zero decked sbc exactly 9.025", where as a factory deck height would be above that, say approximately 9.050????

So basically if I used the compression height calculation, if I had a 9.025" deck height, is this on a "zero decked" block, meaning that my piston would be .004 down in the hole still?

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'71 RS/SS pile of parts: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / 12"/11.1" 4 whl discs / big sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

[This message has been edited by Chuck78 (edited August 09, 2005).]

go figure, the pistons in the size I would need are intended for AMC/Jeep/Eagle L6 242 / 4L 1987-95!

Both the chevy pistons for a 305 and 307, and the AMC/Jeep pistons say they have an offset pin. Would this offset amount vary much between manufacturers, or throw a wrench into the idea?

http://www.kb-silvolite.com/images/spiston/L2229c.gif

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'71 RS/SS pile of parts: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / 12"/11.1" 4 whl discs / big sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

[This message has been edited by Chuck78 (edited August 09, 2005).]

The offset should be in the area of .060 or so, shouldn't be an issue unless you install them backwards, but arrow or notch forward should work regardless, engine rotation is the same, and the pistons won't know what engine it's in. (or care) Honing the pin ends of the rods is no big deal, although you need a proper stone or you'll be using up a bunch of stones destined to hone brass. You also need to make sure you don't have a piston skirt to counterweight clearance issue, and that the width of the pin end of the rod isn't excessive. Your biggest hurdle, no valve reliefs nor is there likely to be enough material in the lids of the pistons to cut a proper valve pocket. (intakes especially) You will absolutely have to balance and you may have to clearance the block similar to a 383 build.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

<font face="Arial,Verdana" size="2">Originally posted by Chuck78:
GMC 305 big block 6 cyl.</font>
What the hell? http://www.nastyz28.com/ubb/confused.gif Please clairify......



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I'm off the antifreeze and the car is tipsy,
On the offramp doin bout a hundred 'n fifty!
71 camaro 427BBC 500+ Hp
Check out My cardomain page! (http://www.cardomain.com/memberpage/814239)

I think he's referring to one of the old "stovebolt" straight 6s they used a lot way back in the day. They made some pretty big ones for trucks back then, although I don't recall a 305. Anyway, they're heavy and long and not exactly the easiest or cheapest way to go fast.

Then again it's not hard to get a stovebolt to 300hp with NO nitrous or turbo.... http://www.nastyz28.com/ubb/smile.gif

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I'm off the antifreeze and the car is tipsy,
On the offramp doin bout a hundred 'n fifty!
71 camaro 427BBC 500+ Hp
Check out My cardomain page! (http://www.cardomain.com/memberpage/814239)

Yup, 305 was a V-6 used in many GMC trucks and heavy duty trucks. There was another V-6 that a friend of mine has in his GMC dump truck that I believe he said was a 325 CID. Now that was a surprize to me, but I guess the 305 V-6 was a beast.

Steve

I tell you what, I would pick up a "CHEAP" 307 AND play with it before I would mess with a 305 or the 262 or 267..

BUT I bet if you dropped a 283 crank in a 267 and made a 230" motor out of it, it would rpm to the MOON!!!

Don't get me wrong here b/c you can make 305 run, but I just like the bigger bore, short stroke motors better unless I was to build a 4.00" or 4.125" blocked motor AND then stroke it for max. cubes...

pdq67

[This message has been edited by pdq67 (edited August 12, 2005).]

"Zero deck" means your block is decked so your pistons are 0 in the hole. 1.74(stroke)+ 5.7(rod) +1.560(piston)= 9". You would need to remove 0.025 from the deck to have a zero decked block.

That's where you get the stock, generally, .025", "down in the hole" piston location.

9.025" -.025" and go from there unless you want to use a pin height that zero's the piston deck at the 9.025" height or deck the block, .025" to 9.00"...

pdq67

Those Jeep pistons would do just that, my overall crank/piston/rod height would put me at 9.021" then, so I would pretty much have a zero deck with the factory deck height on the 307 block. Thanks for clearing up the confusion.

Now back to one of my original questions - what about the vortec combustion chamber in a 3.905" bore vs the 350sbc's 4.000" bore??? Is this still going to work fine? That's .0475" less space from the cylinder wall to the edge of the combustion chamber. Seems pretty minimal to me.


With gas going to $3/gallon here very soon, the idea of doing a late model TBI 307 clock / 305 crank (334cid or so) sbc in my proposed project daily driver 63-66 GMC Suburban (with a 5 speed for the extra on the top and bottom) is much more a appealing than just taking out a late model 350TBI, considering that I already have it all except for the vortec heads and 305 crank. I guess I would probably take a 4WD truck if I found one, as that would be really nice to have sometimes, but there goes a bit of the mileage factor... Besides, a 327 was the biggest any 60-66 suburbans ever got, second being a big block 305 GMC 6 cylinder. the rest were in the mid 200's, displacement-wise.

so what about the vortec chamber on a 3.905 bore vs stock 4.0?

and would the 334 really have to work that much harder (with a 4 or 5 speed) and use more gas vs a 350TBI that wouldn't have to work quite as hard / use as much gas to pull a big truck like that?

Basically, what it comes down to is mileage. Don't know the theories on efficiency of internal combustion engines with lower power vs more power/same load. Any thoughts?



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'71 RS/SS pile of parts: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / 12"/11.1" 4 whl discs / big sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction