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Discussion Starter · #1 ·
so..............I'm not a s10 guy
however I'm plan on putting a 4.3 into my jeep buggy
anyone know where I can get some good info and tech on the 4.3
a few questions to start with
1: anyone know the average weight of a 4.3?
2: performance upgrades?
3: what years are the best years of the engine?
and whats with the vin letter and it's signifigance?


Thanks in advance, and if you feel the need to flame me b/c I don't have an s10 go for it, I don't mind a good laughing
 

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Molon Labe
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1: I'd guess about 400lbs (not completely sure but thats what an old 3.8 felt like)
2: Performance upgrades galore
3: 96+ (Vortech)
Most newer engines are W coded. There are some differences in horsepower among the different Vin codes. W is common and probably the best to look for.

However, if you're just putting a 4.3 into a buggy, then you could get an older one and carb it to keep things a little simpler.
 

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The best heads in my opinion are the '96 and up vortec's(flow wise). These heads will bolt up to any 4.3 block. The '00 and up vortec's have 8mm rocker stud holes if you plan on doing roller rockers you can find a bolt in stud, other years you have to get creative. These heads have a different intake manifold bolt pattern. If you are going carbed it is easy to just get the edelbrock 2114 intake manifold to bolt up to them.

The '92-'95 cpi motors had the biggest cam in them. The tbi's, and '96 and up's had mild cam's, and they should react well to an aftermarket cam, the stock cams should make good torque though, i guess that is probably what you would be going for. The '96 and up vortec heads have a .480" lift limit stock, the retainer to seal is where this problem it. The guide must be cut lower to get more lift.

Vin's:
W, cpi, '92-'95 195hp/260trq
Z, tbi, '88something-'95 160hp/230tq hp may be lower for the older years
w & x: csefi, '96 and up, both motors are the same
Edit: 180-190hp/240-250tq
 

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Discussion Starter · #4 ·
rat said:
The best heads in my opinion are the '96 and up vortec's(flow wise). These heads will bolt up to any 4.3 block. The '00 and up vortec's have 8mm rocker stud holes if you plan on doing roller rockers you can find a bolt in stud, other years you have to get creative. These heads have a different intake manifold bolt pattern. If you are going carbed it is easy to just get the edelbrock 2114 intake manifold to bolt up to them.

The '92-'95 cpi motors had the biggest cam in them. The tbi's, and '96 and up's had mild cam's, and they should react well to an aftermarket cam, the stock cams should make good torque though, i guess that is probably what you would be going for. The '96 and up vortec heads have a .480" lift limit stock, the retainer to seal is where this problem it. The guide must be cut lower to get more lift.

Vin's:
W, cpi, '92-'95 195hp/260trq
Z, tbi, '88something-'95 160hp/230tq hp may be lower for the older years
w & x: csefi, '96 and up, both motors are the same
Edit: 180-190hp/240-250tq
wow I'm impressed, that type of info is exactly what I was looking for, usually on other forum boards, you have to weed through the bullsh1t to find out who knows their stuff, it's obvious that you do and I thank you for your input
now for acouple of follow questions
difference between cpi and tbi I know tbi is throttle body injection but what is cpi, and from my now understanding a cpi engine has more torque and thats what I'll want along with fuel injection, now would putting on a newer vortec head on an older cpi engine be beneficial?
 

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The cpi made more torque, i think the rating was up at 3600rpm though.

Cpi has an injector in the intake manifold centraly mounted, then little tubes with popets at the ends. It is multiport injection. Edit: these are prone to leaks.

Getting a cpi to bolt up to vortec heads would be a pain. The intake ports are .100" taller, so material might have to be welded to get the ports covered. Then the heads would have to be drilled for the old style patern. Doable, but not worth it. The cpi heads flowed better than the older tbi heads. I think tbi's got the cpi heads in the '94.5-'95 time frame but i could be wrong.

If I was doing what you are this is probably what it would look like.
Early 90's-'95 tbi may or may not have a ballance shaft, try to avoid the really early ballance shaft motors, like around '92

'00 and up vortec heads if you want an adjustable valvetrain, '96 and up if you don't care

A mild cam, depends on if it has a ballance shaft or not really, but something like this:
http://www.cranecams.com/?show=brow...ze=4.3 L&partNumber=1439811&partType=camshaft
Should have a smooth idle, good torque, but an extended rpm range over a tbi. More exhuast duration than the cpi cam, but less intake duration. No vortec head modifications required. The exhaust flow on the vortec's is terible, this is why i like this cam. It will not go into a non ballance shaft motor though.

And then put an edelbrock 2114 carb intake on. Get a tbi to carb flange adapter, and bolt the tbi on top. No provisions for egr, and there is a bit of work to get everything bolted up.

Tune from www.tbichips.com

Here is the camshaft specs in the various 4.3's for refference: http://www.s10forum.com/forum/showpost.php?p=2764688&postcount=2
This is from a sticky from the top of this forum, lots of detailed 4.3 info: http://www.babcox.com/editorial/ar/ar40047.htm
Here are the stock '00 up rockers compared to comp pro magnums, they have roller trunions: http://community.webshots.com/album/466765008qMgZLp
 

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It is a pain to try to put '96 and up vortec heads under the cpi intake manifold. You are best leaving the stock heads under the cpi. The cam in the cpi is already fairly agressive, i wouldn't go with any thing bigger for what you are trying to do.

I was saying get a tbi motor. It is still fuel injected, it just has the fuel injectors on the throttle body. Then bolt the throttle body onto the carb intake that bolts to the new heads. Then put a mild cam in this motor. The major chokeing point on this motor was the heads and cam, both of which you would solve.
 

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Id get a 96 or newer and put the 2114 intake and a carb on it... or you could use the fule injection.... if its an off road vehical a carb would flood out on steep inclines. Also if your going to be going up and down steep inclines you need to wory about oil control. With the stock oil pan going down a Relly steep hill you will loose all oil psi.
 

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