Hi all, got a 95 Jimmy with the CPI motor in it and 1st gen 4L60e. I'm wanting to do a v8 swap (nothing fancy) and am wanting to keep the original transmission and transfer case. I am wondering what would be the easier route. Should I just find a 350 TBI and wiring harness from a truck that had the same drivetrain? Or should I just get a 350 with a carb? If I went carb, I'm not sure how to do any modifications to the PCM to get the trans to work properly. Any and all advice is appreciated!!

 

What ever you go with you will need a TPS plus a lot of other sensor input from engine. I really don't know what would be involved in this swap. Maybe someone who has done this will chime in. Good luck and keep us posted on how it works out.

 

Well I understand that if I go the TBI route, I will need the wiring harness and pcm for it, and just swap that in as well, leaving all the sensors and wiring, I just need to make sure the TBI pcm is compatible with the the 4L60e. Thats why I am curious about the carb route as well.

 

There is nothing easy about swapping a v-8 into a second gen s10/Blazer. Tons of projects out there have been started and never finished or cobbled up beyond recognition.

Things to keep in mind:

1995 L35 4.3liter v6 CFI 195hp@4500
1996-2002 L35 4.3 liter Vortec sequential MPFI v6 200hp@4400
1988-96 L05 350 v8 w/TBI 210hp@4400

Why would anyone ever bother to go through the hassle of swapping in a TBI v-8 and making everything work?

1996-02 L31 350 v8 Vortec sequential MPFI v8 255hp@4600

This is the only swap retaining a fully functioning PCM that makes any sense but in your 1995 still would need to use/adapt PCM/wiring from 1996-1997 and have the ability to program PCM and verify all wiring in order to make it work. Blazers have a lot more than just the transmission to worry about.

Too bad you don't have a 1996-2002. Then the Vortec V8 is a decent swap without much computer hassle - use the same accessory brackets and PCM and wiring (just add a couple of wires for the 2 extra injectors.

If you don't care about emissions and are building an "off-road truck", if you retain the engine sensor inputs like TPS, MAP, tach, temp, etc and use a carb, the transmission will shift. Now the TCC will never engage and you will burn up the torque converter and possibly the trans with heat if you drive a long while in OD - but the increased torque of the v8 will probably take out the trans anyway. That is, unless you do some custom programming of the PCM to allow the TCC to engage with other systems inop. Again, these swaps into second gens are not for the timid.... unless you plan on gutting the accessories completely and making a race car out of them. Lots of systems interact with each other.

Here's some reading if you care to buy the book.
JTR Chevrolet S-10 Truck V-8 Conversion

 

Thanks for the link on the v8 conversion Lesmyer! If you have an early style 4L60E without the PRNDL switch on the side of transmission ( neutral safety switch) could make it shift manually with a switch for lock up. Would be a PITA for daily use.

 

I know the swap isnt easy. To do the MPFI v8 I would have to rewire everything, and then some because mine is the bastard year OBD1.5. Thats why I am leaning toward the TBI, essentially downgrading I know. I presume carb is out of the questions then since that would be the most custom work trying to get all those sensors working and doing the reprogramming.

 

It's just that you have a particularly bad year for a v8 swap. I have heard of using the existing PCM for trans control and gauges with a carb but I have no experience in doing that. It was on one of the S10 V8 forums. If you're bound and determined to swap a v8 in there, that might be your best bet.

 

Yeah I understand that, lucky me lol. Thanks for the info though, I'll search other forums to see if I can find some answers.