4.3 TBI to 350 TBI swap

[texas tough]

keep in mind manuals run a little higher idle RPM than automatic trans. also 4.3 injectors are different than 5.7. I learned this after chasing an idle,. surging, lean problem for a long time,. bought truck as basket case, had blown head gasket, some parts were in the bed, some in the cab. short block was in the engine bay. I just assumed the intake and throttle body belonged to that truck. I TRIED EVERYTHING, from fuel pump, to 02 sensor, distributor, and on and on and on. I got the numbers of the injectors looked them up and they were for a 4.3.. went to salvage yard, got a set out of a 5.7, verified part numbers, and the truck ran great.!!! be very careful swapping parts around,, ALSO there were ALOT of changes in the 4.3 parts over the years.
DO NOT RUN 4.3 INJECTORS IN A 5.7 !!!

 

[FrankieD61]

keep in mind manuals run a little higher idle RPM than automatic trans. also 4.3 injectors are different than 5.7. I learned this after chasing an idle,. surging, lean problem for a long time,. bought truck as basket case, had blown head gasket, some parts were in the bed, some in the cab. short block was in the engine bay. I just assumed the intake and throttle body belonged to that truck. I TRIED EVERYTHING, from fuel pump, to 02 sensor, distributor, and on and on and on. I got the numbers of the injectors looked them up and they were for a 4.3.. went to salvage yard, got a set out of a 5.7, verified part numbers, and the truck ran great.!!! be very careful swapping parts around,, ALSO there were ALOT of changes in the 4.3 parts over the years.
DO NOT RUN 4.3 INJECTORS IN A 5.7 !!!

Thank you.

I got everything running; I just need to get it running right. I have not loaded up the tune, I'm using a TB with 4.3l injectors and a bunch of other stuff.This project has been such a long one I'm just so eager to get the truck home, clean it, and get it running right.

I have a TB from a 350 with the correct injectors but it's leaking like a busted pipe (after a fresh rebuilt)... I have the new gasket set coming from rockauto. The leak is coming from the fuel pressure regulator gasket which was a giant pain to get back on..

A huge thank you to all of you guys for being so patient and having some great tips. A special thank you to @PlayingWithTBI for the Flash-2 suggestion.

My work is far from done but the BIG stuff is done!! The motor runs like a top (even with a tune that's not calibrated correctly; I haven't loaded my tune yet, a throttle body from a 4.3l with the wrong injectors, deleted EGR and no cat). The thing sat for 5+ years and didn't even tick or rattle on first start up.

Anyways, thanks guys! If I have any other questions I'll be sure to ask.