The motor is blown in my 96 formula and I have the option on buying a 94 LT1. I was told that they are not a direct replacement due to the wiring harness. Is that true?
Brandon

 

There are differences between OBD-I and II that you will have to contend with. You can do it, but you will have to swap some things from your old engine.

 

Is it tough things to change or easy? Should I just look for 96-97 motor?
thanks
Brandon

 

The crank sensor would be the hardest thing, but thinking more about it, the 94 is going to have a non-vented opti, so that is going to cause more problems when trying to swap over the front cover, reluctor for the crank sensor and vented opti. You would also have to swap the cam. That may be more than you want to do. Another solution would be to have the crank sensor programmed out. Then you would not have to swap those parts.
If you don't want to mess with it, look for a 96-97.

 

Since you will have both motors out it will be pretty well cake, just buy an oil pan, front cover, and intake gasket sets.

With both engines out remove the front cover of both motors (waterpump and opti will need to be removed if not already).
Remove both timing sets keeping all parts from the 96 in order , you will reuse these (I would reccomend a new timing CHAIN at this point unless the gears are wore pretty good as well, then change the whole timing set)

Remove the keyway from the cranks and put the 96s keyway into the 94s crank. Remove intakes from both,remove lifters (use best set) remove camshaft and swap (lube liberally). Install the 96 timing set onto the 94(line up the dots), slide on the cranksaft sensors reluctor onto the crank snout,install the 96s timing cover onto the 94 motor, install the 96s opti onto the 94, reinstall lifters (lube liberally) and retaining system. button it all back up.

I forgot to add, you'll need to use the 96s coil and ign module as well.

 

Also have to swap the knock sensor.

There are some differences in the vacuum connections on the drivers side of the intake manifold, and on the routing of the PCV vacuum. That will require that you tee the Opti vent vacuum line into the connection for the EGR solenoid vacuum line.

You will need to swap over the EEC purge solenoid vacuum lines, and the EEC flow detector switch. There are also differences on the AIR system, including a vacuum connection and a purge valve (depends whether your 96 had the AIR recall done).

Swap the exhaust manifolds, since the AIR plumbing connections on the manifolds are different.