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4.3 vortec to 5.7 vortec

8K views 3 replies 4 participants last post by  jwglover 
#1 ·
allright well im not new to the whole v8 s10 scene i have previously done a 91 sonoma and a 95 sonoma and am wanting to now do my 97 jimmy. The Jimmy is 2 door 2 wheel drive , auto. This time i wanting to go efi and pretty stock looking as my last 2 were 12 second trucks and actually scared me to drive cuz the ass ends swung out everywhere. Both had the same motor (transplanted same motor into both) both had 4.11 with zexel torsen and caltracs and actually got one to pull front tires off ground doin 45 in the rain.

Now i would like to put a 96-99 (i belive those are the correct years.) 5.7 vortec into my jimmy. And im actually wondering about what it would involve as far as wiring and the exhaust. I would like to build the 5.7 up a little bit mild cam, .030 over maybe 9.8:1 comp. ratio. Now with this motor i would like to keep the stock wiring harness and comp ( comp reflashed of course.).


1. if i were to use the stock 5.7 exhaust manifolds would i get lucky with them aligning with the stock exhaust ( maybe temp not sure yet).

2. how would the stock wiring work as far as the wiring for the spider injector and i believe that the 5.7 has 4 O2 as apposed to my 3

3. Will i be able to drop the 5.7 into the stock location of the 4.3 minus it being longer in the front.

if anybody has done this swap i would really appreciate any hints or tips on this particular swap.

now i do know mostly what i am getting into and know the 4l60e in stock form may not last long and that i will be building one but i would like to keep this swap "stock". i would like a nice reliable good running v8 dd.

thanks to all!
 
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#2 ·
1. if i were to use the stock 5.7 exhaust manifolds would i get lucky with them aligning with the stock exhaust ( maybe temp not sure yet).

I wouldnt go through all that work and not do headers. Plus I believe you need f-body manifolds otherwise they will hit the firewall. headers would wrap around the steering shaft.

2. how would the stock wiring work as far as the wiring for the spider injector and i believe that the 5.7 has 4 O2 as apposed to my 3

all you do is add two wires from the spider harness to the ecm, move the temp probe, and adjust harness accordingly. you will also need to switch around the wires for the rest of the injectors as they fire in a different order. As for the remaining O2 sensor, you could either add the wires for it or ignore it. post-cat o2's dont control the mixture. you can register on ac delcos website and have access to all the wiring diagrams you want for 3 days, print off anything you might need.


3. Will i be able to drop the 5.7 into the stock location of the 4.3 minus it being longer in the front.

for the most part, you might not clear the radiator though. electrics fans are a must, and look into a better radiator if you are in a warmer climate.


good luck!
 
#4 ·
I was almost ready to post up most of the same idea, I want to drop in the 5.7 and throw the 4.3 away, I want to know if the wireing is the same, exhaust is not really an issue (you can deal with that ) but if th wireing will plug right into the top of the engine that would be an easy swap.
I am working on a 98 4dr blazer, rad will be moved forward, and exhaust will be done at a muffler shop, motor mount can be moved, but can the wireing plug right into the 5.7 ?
 
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