Hey guys,

Im buying a 1993 LT1 with trans (4l60/700r4), computer (unknown numbers, but original with the engine), and the engine harness. Im going to post stuff that I know about, and then ask some questions.

Swap is going into a 91 firebird w/ the 3.1L V6 with an auto (700r4) trans

1993 trans

trans is called 4l60 but its the exact same as the 700r4 found in our 3rd gens. This means that I can take my tailshaft and put it on the back of this trans, and it should bolt up nicely to my cross member and the torque arm will work as well. Since this isnt the 4l60e, which came out in 94 it will be a direct swap in.

Questions:

can i use any sbc 350 mounts?

Wiring is going to be the hardest part of this swap for me. Ive read through the links on the "LT1 Faq" thread, but im still lost. I was wondering if there is some type of plug and play harness i could buy for a reasonable price. Or if anyone has one for sale, i might be interested in purchasing one.

Do i need the fuse box from the LT1 car, or will my fuse block be sufficient?

Being a 93 set up, this car would only use an ecm right? Pcms came out with the 4l60e in 94?

 

From 89-93 the 700R4 was reclassified as the 4L60. There were some minor internal upgrades, but the unit was essentially the same. I actually used a 4L60 from a 93 Z28 to replace the failing auto in my 92

Why are you swapping talhousing? Is it a corvette pullout? If its a 4th gen, the stock tail will work

SBC mounts, yes. 4th gen LT1 mounts are different for one side, cant remember. One side is SBC

Plug and play wiring, not really. Id recommend using a newer PCM with the swap. The old ECMs are not far from TPI ECMs and leave quite a bit to be desired. Read over the LT1 harness start to finish thread

Your fuseblock will suffice. If you do order a new harness, an off the shelf version will likely come with a fuseblock making it stand alone. This will render many fuses in your stock block redundant

Correct. ECM stand for engine control module, while PCM is powertrain control module to incorporate advance automatics. Delphi took a step back for some of the newer GEN IV LSx and divorced the PCM to ECM and TCM on some applications. Dont confuse those with the BCM or body control module which controls non-powertrain functions like RAP retained accessory power, keyless entry etc and is not related to the swap

 

I thought the tailshaft would be different, so that's the only reason I said that. Since its the same, I won't be swapping mine over.

As for obtaining a pcm, what would be the advantage of this? If I'm not running the 4l60e, does it even make a difference?

This might be a dumb question, but I'm going to ask anyways... Would it be possible for me to disconnect my engine&harness from the comouter currently in my car and just throw the LT1 and its computer in their as well? In my head it seems like all I need to control is the engine, and not any of the other sensors.

 

did you get the 16159278 ecm with the 93 engine ?

 

I haven't been down to see the set up, the seller is out of town for the next few days. He said that he's off Friday, so ill check all the numbers then

 

If I were you I'd hit up a junk yard for a 94-95 computer and harness. The '93 if I'm not mistaken is a batch-fire system meaning it fires all injectors on a given bank at the same time. It's also a speed-density system (no MAF) which in my preference is a little more difficult to tune. Others may feel differently on that. I feel your pain on the wiring, but really you can do it. It may not be easy for you but it is possible. There are enough resources around to give you all the info you need. Both PCMs and harnesses are available on ebay, the PCMs being pretty inexpensive, the harnesses a little more pricey.

 

Agreed fully with the above..
1993 f body has a "one of a kind,PITA harness and ecu" the 94-95 is alot better to work with or even go the efi connection route using an Ls1 pcm and custom harness 10x easier to tune since most tuners have efi live etc...

Read up on the other upgrades for 92 93 Lt1s like 95-97 opti sparks since they are vented units

 

okay, so what im getting from these replies is that the 1993 ecu is not as good as a 94 ecu. Are you guys also saying that if I find a 94 that it will be easier to wire up?? The difficulty of wiring is literally what will determine if I do the swap.
Also, to my understanding the 4l60e came out in 94 and it has a different mounting spot on the crossmember than the 700R4. Should i buy the entire 93 setup (engine, 700r4 trans, wiring harness, and ecu) and then go to jys and look for a 94 ecu and harness?? Do you guys know if the early 4l60e will bolt up to my cross-member (also, if they do bolt up, which years will fit?)

Edit:
should I just look for a 95 setup instead (for the vented opti)

 

94/95 is the same size and bolt pattern as your 700. 96/97 uses a smaller vss sensor on the other side. It bolts up to your 700 so I'd guess it works too. 98+ had the 6 bolt tail housing; moves the mount into a farther location. That's what I gathered in the last 3 years. Hope it helps

 

oh okay, so i can use upto a 97 transmission with my stock crossmember?

 

You shouldn't have an issue with the 96-97. Just check. 96+ is a better trans but you have to use a 95+ computer due to pwm. The trans has to match the computer.

 

you just pull the lt motor mounts off and pitch them then get the standard SBC clam shells bolt them on; move the saddles "or replace them with V8's mounted in the right set of holes, and your are golden, note; if you are going to use the ac you will have an issue with the SBC RH motor mount, that is why the RH LT1 mount is moved back to clear the compressor, and you will need to notch the K member to clear the compressor, I personally went with the Vett system moves the compressor high and left

 

I'm not sure that that is entirely true, I think that the PWM can be "bypassed" then you wont need a 95+ ECU to run it??

 

Yes it can be bypassed. I wanted to use a 94 trans with my obd2 swap and it just seemed like too much work. I just ended up building a 99 s10 case to avoid all the trouble.