Throttle body V6 to V8 conversion question.......

[80ECLT]

You can use the 4.3's harness just upgrade to a V8 throttle body if you can (dirt cheap used @ junkyard) Like said the tbi system is dirt simple, and the part numbers are the same for all engines in the same area. I believe the fuel pump is the same too, just can check that first...

 

[Deuce4935]

QUOTE: You want to use the entire v-8 setup, that MEANS EVERYTHING that came on the v-8 engine from intake to the oil pan. If you put a v-6 tb on a v-8 engine of course its going to run lean, if it were that simple without repercussions then the factory would have loved saving money and going that route. Save yourself the time, energy, money and frustration and do it right the first time

Agreed; but why would I need the entire wiring harness; if the car is already TBI equipped? I do have access to a complete TB V-8. And I could see where I would need the V-8 ECM to control pulses to the Throttle body.. Anyway; I'm not arguing with anyone; I'm the one who came on here asking for help. I know the easiest thing to do would be to put my Holley on and a MSD distributor and forget it. But I'm looking for something that is very reliable and has good idle quality ( just opposite of what I've been doing since I was 17) This isn't going to be a street/strip 11 second ride. I've got that.
Anyway; on the ECM; will any 87' - 95' V-8 TB work to fill the bill or is there specifics that I need to be looking for?
As far as rear-ends go; I've got 8.5's and the transmissions aren't really an issue either. I've got access to those as well.
I appreciate both of you guy's input; Im just trying to get a game plan going here where I can gather up everything to get it up and running right.

I'm sorry, but I wasnt understanding the your question until now. By all means, you can use the v-6 wiring harness and computer. I dont know why I was missing that, sorry for the confusion guys! But also get the v-8 tb.

 

[cooke]

QUOTE:I would suggest an adjustable fuel regulator, or dilling out the brass and making the stock HTH

Why would I need the adjustable regulator? Did you run into problems on your conversion without one? Sorry but I don't know what the "HTH" is.
I appreciate everyone's input on this deal. I'm going to try and move pretty fast on this deal. I'm going to try and use an otherwise stock TB short-block with a very mild cam, 96' Vortec heads, re-drilled TB intake and some headers.
Again, thanks for all the help.

 

[87SS-ZZ3]

4.3 injectors are rated at a lower flow rate. By increasing the fuel pressure you can overcome a lean condition (the injector pulse rate will stay the same but more fuel will be sprayed out) My sentance got cut short. You can make the stock regulator adjustable or by one that is already adjustable to up the pressure. I have seen the need for increasing fuel pressure, but engine combinations differ. HTH (Hope This Helps)

 

[cooke]

Thanks, now I understand. Also, thanks for helping me out on the "HTH" code. I'm a "DA" when it comes to computers; where it be in my house or on my car. I was born a little late :lol:

 

[malibulvr]

Ditto on all said. I did the exact same swap years ago used a truck 350 tbi engine. Only thing I changed was to the truck 350 throttle body. Suggestion, if upgrading to a little bigger cam, and vortec heads that wil flow well, spen the money on a Holley throttle body cause it's few more cfm and all the sensors are adjustable. Had one of these on an early 90's Chevy truck and it made a big difference over a stock one. Good luck with it!

 

[87Aero]

I'm going to keep an eye on this thread. I could go this way too.

I've got a shop manual from the dealer I worked at for an 86 G and B bodies. If you need some good wiring schematics, let me know. I'll get you color scans or photos.

Scott.

 

[cttandy]

Yeh, I have seen a lot of local guys do this. I sold them the engines on many occasions.

It will bolt in and swap over, if you do your homework. Actually, even the drive accessories should bolt from the 4.3L to the V8. Everything should plug in from the original harness to the 5.7. I have installed a 5.7L TBI on a 4.3L engine. I swapped injectors, but only because I didn't want to run the engine to rich. The 5.7 and the 4.3L injectors look the same, if you have the right TBI units (they changed several times a year at one point). I worked at a salvage yard at the time and just went though till I found the right one. If I am not mistaken, the part number for the pump is the same for a 4.3L and a 5.7L, so I don't see it needing any modifications there.

If your wondering, the TBI got smashed in the wreck. It started acting weird about a year after I fixed the truck.


Sounds like a pretty simple straight forward swap to me. Change the motor mounts, find the injectors with the right plugs for your harness, correct fan shroud, and done!


You can also get a vortec 4.3L from a later s-10, and get the TBI vortec intake from 93-94 full-size 4.3L truck. It will all bolt in and be about 40 HP over the stock 4.3L. But, if the engine is already out, why not stick something big in it.

 

[big-angry-hillbilly]

why not stick something big in it.

That's what she sa....nevermind.

Three letters and three numbers my friend:

TBI 454.

 

[Doober]

Three letters and three numbers my friend:

TBI 454.

+ a Dynamic EFI setup, then you can run a healthy cam in it
http://www.dynamicefi.com/