what kinda electrical mods? can it be fixed with simple programming?

and i know it will physically work with a spacer? where can i get it? cost?

 

Do you mean a bellhousing Spacer?

 

WHile you can make a 94 4L60E mount up in a 99, the 1999 PCM is not capable of running it.

Re'

 

Actually if you put the 99 electronics in the 94 in particular the PWM solenoid and the 3-2 solenoid and wiring harness. The 99 PCM will indeed run the 94.
The PWM solenoid will simply act as a dummy to fool the PCM and will give the same effect as eliminating PWM comonly done with the later transmissions anyway. There is a 3-2 strategy difference however ion actually having driven cars this was done in on several occasions I have noted no decernable difference in performance caused by this personally.
Ideally however I would just get the right trans for the car seems like would be alot less trouble.

 

who has done this? i need to know if the spacer needed is a flywheel spacer(that moves the flywheel towards the tranny...

or a crank snout spacer..the one that comes with a tci flywheel...

or both?

 

just did this last night...and its not that straight foroward and people have it wrong with the spacer...its a sleeve...the converter actually is about 1/16 from the flywheel when bolted up...no spacer needed...problems is the snout of the converter is smaller diameter than the hole in the back of the ls1 crank...ls1 have bigger snouts...SO you need a sleeve like one that comes from tci with their flywheels

also i believe they are differant bolt patterns on the converter, which is one more reason to run a tci flywheel, one bolt pattern works for lt1 one for ls1

the tranny lines are screw in on a lt1 car not on a ls1 keep that in mind

and the speedo sensor is a differant plug on a lt1 tranny then ls1 harness...tailhousings and sensors are NOT interchangable you need a new plug...

and as per performabuilt told me you need to change harnesses inside the tranmissions...simple to do basic mechanic skills can accomplish this, also the 2 solanoids in the front of the transmission helt in with clips need to be swapped...one will be missing on a lt1 transmission