LT1 Swap

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05-25-2006, 04:44 AM
mfrancis83

Hello all. Im new to the sight, but shouldve joined long ago. I have a question about an LT1 swap into a 91 chevy 1500 (short bed, single cab, 2wd). Ive got an LT1 out of 96 Z-28, with the complete wiring harness and computer, but no tranny. I know that they are crap, but i have a built 700r that im hoping to put behind it. My question is weather or not i need to get the PCM re-flashed to account for me not running an electronic transmission. I have also been debating a painless wiring kit to simplify the swap as well as bypass the VATS. Any information that can be thrown my way would be appreciated.
05-25-2006, 08:15 PM
kwkenuf

<div class='quotetop'>QUOTE(mfrancis83 @ May 25 2006, 02:44 AM) [snapback]53991[/snapback]</div>

Quote:

Hello all. Im new to the sight, but shouldve joined long ago. I have a question about an LT1 swap into a 91 chevy 1500 (short bed, single cab, 2wd). Ive got an LT1 out of 96 Z-28, with the complete wiring harness and computer, but no tranny. I know that they are crap, but i have a built 700r that im hoping to put behind it. My question is weather or not i need to get the PCM re-flashed to account for me not running an electronic transmission. I have also been debating a painless wiring kit to simplify the swap as well as bypass the VATS. Any information that can be thrown my way would be appreciated. [/b]

As long as the 700R has a VSS (or you can adapt one), you'll be able to make it work. Have the PCM flashed for a manual trans so it won't be looking for any feedback from the tranny. If you don't plan on running the resistor key in your starting system you will either need to disable VATS in the PCM or get a VATS override box (got mine from John spears about a million years ago for my Camaro)
As far as harnesses, it depends on your capabilties and the time/money you want to spend. You can modify your stock harness to work for basically no dollars or you can buy a premade harness from one of the vendors. A third option is to have your stock harness modified by one of the vendors. Any way will work, but if you have the ability and time to rework the harness yourself, it is the most rewarding of the three.
05-26-2006, 05:04 AM
mfrancis83

Thanks for the info. I was doing some trading with the guy i got the engine from, and he is willing to swap my pcm with one from an obd1 manual car (not sure of the year). Will this work with my later engine? I understand that i will need to get it flashed regardless of which pcm i go with because i plan to change some of the internals, but am interested in the less restrictive obd1.
05-26-2006, 08:00 AM
RedHeartbeat

The older PCMs use an EPROM and that is old technology. I like the newer PCMs from the OBDII that are open ended and easily programmed. I had a 93 LT1 and had to send off for programming. You can do your own PCM programming with the OBDII PCM.
05-30-2006, 01:35 PM
kwkenuf

94 and 95 OBD I PCMs are programmable also just like the OBD II stuff. Not as many bells and whistles but a non-removeable chip same as OBD II... Transition years. LT1 Edit can be used or most tuners can still hook you up. If you have an OBD II LT1 or LT4 engine (1996) you can run OBD I on it by swapping PCM, harness and knock sensors. After the swap you will no longer have to worry about the after cat O2 sensors either since they are an OBD II "feature". Do a forum search on the F-Body web site for more detailed info on the swap.