4.3 TBI on a 5.7?

CrustyJeep · Oct 8, 2006

Let's say a guy was sick of his POS carb on his SBC 350 and wanted to put TBI on it. Now let's say this guy just happened to have a complete '88 4.3 (taking up way too much space) in his garage with harness and ECU and everything.

How many of the parts on the 4.3 would work on the 5.7? Throttle body? Most/all of the sensors? Wiring harness?

Any Chevy techs around?

TreeClimber · Oct 8, 2006

Glen

I believe the following to be correct, but, alas, I am not a chevy tech

All the sensors and wiring will work. You will need a new computer. However, the throttle body required a EFI intake maniford, and the EFI manifolds are bolted into the heads with different angles on the bolt holes. So you must swap heads -or- machine out the EFI intake manifold to fit the existing heads -or- find a 454 manifold, which used a adapter to fit the throttle body onto a holly-type spread bore manifold.

CrustyJeep · Oct 8, 2006

If I have a factory manifold with a quadrajet on it, is that "spread bore"?

I'm such a GM noob :redneck:

TreeClimber · Oct 8, 2006

You need one of these. If it doesn't directly bolt to your carb holes (because Holly's are square pattern, and Rochester Quadrajunks are slightly wider in the back), it shouldn't be that tough to redrill it.

here's the link http://69.20.110.81/index.asp?PageAction=VIEWPROD&ProdID=126093

edit. Holly is generally considered a Square Bore, Rochester Q is generally considered a Spread Bore. I also don't think often about GM, and my verbage is poor. My bad.

And according to the linky, this should bolt directly up to your manifold.

no excuses · Oct 8, 2006

If u use the TB from the V6, u will need to swap in some injecters from a 350, TB is the same, injectors are different. I would just look for a TB from a 350.

hackster · Oct 8, 2006

Id just buy some new injectors for a v8 and throw them in your tb. Howell was a great resource for me on my tbi setup on a jeep. They can setup your computer anyway you want it. If you want to talk to them ask for Tom, he really knows his stuff. Other than that you should be home free.

Sean