jamesbern

First off this is a 95 Chevy pickup, but I need the TBI gurus help. The pickuo currently has a 4.3 V6 and we will be building a mild 383 for it. The ecm and most sensors will transfer over along with the accessories I believe. The problem I see is the 4L60E tranny that is in it. It is the biggest problem I foresee in the swap, but another might be tuning of the 383 with TBI. I realize we will need a 350 intake but that is taken care of. How hard will it be to get the computer right and retain the trannies services. Please help if you can.

dimented24x7

iTrader: (2)

Your present pcm, or some other tbi pcm, would probably work with teh V8 provided you made some changes to the bin. However, IIRC, the V6 trans has fewer frictions in some places then the V8 trans'. Itll slip behind a 383. Better solution would be a properly built 700-R4/4L60-E/TH350, etc. Your choice on which you want.

EDIT: I could be wrong about the trans, but I remember someone having problems with a 4.3L trans and a V8.

90RS305

Get a T-56, only way to go with that much power in front of ya!

jamesbern

I could build the tranny up to handle the engine myself, so thats not a big problem. My biggest question is the functioning of the early 4l60e as compared to the OBDII computer, are they the same? Would the 350 TBI unit supply a 400 horse 383 correctly if given the right prom?

BMmonteSS

The ecm will run the TBI setup on a V-8 with little tuning. I've done several trucks here locally. The tranny control will work fine if you upgrade the tranny internally. I'd watch out for the 3-4 clutch pack and the 2nd gear band.

Feeding a 400 hp 383 is a whole nother story. If you do some searching you'll see that the max HP that can be fed with TBI is debatable. At a bare minimum you'll have to get a 454 TB with 90 LB/hr injectors and probably still have to turn the fuel pressure up a good bit. The most HP I've seen made with TBI was 390, that was with 90 lb/hr injectors at 15 psi of fuel pressure, and he was static, meaning he needed more fuel. On top of that he was using a crossfire setup that didn't rev real high. (It's easier to feed your engine at low rpm's) Do some searching on the subject and if you have more questions ask away.

HaulnA$$

It should work fine as both applications run the same PCM and same MASK ID, which is OBDI by the way but just has an OBDII ALDL connector in 95. You will need to get a MemCal from a 94 or 95 350 Auto truck, change the constants in the chip to match your injectors and cylinder displacement and start from there. You will also need to use a single 350 knock sensor mounted in the block near the starter instead of the head mounted double knock sensor 4.3 setup. The biggest pain is if you are going to retain EGR function, you will also need to switch to the 350 EGR setup which uses a solenoid in stead of a linear EGR valve like the V-6 and will require a harness modification. As far as the tranny's go, the only difference between the 4L60E V-6 and V-8 applications that I know of is the valve body which can be easily converted . HTH

jamesbern

After more research I have decided to swap in a 700R4 and go with an aftermarket F.I. setup like the Holley 950 Commander. It would be alot easier to go this route from what everyone is telling me. Plus I have the 4L60e sold as soon as I get it out.