Small Block & Big Block Chevy Specific - How can I find out what clutch to use?

I need to replace the clutch and flywheel on my car b/c I think I bought the wrong one.:bang: All I know about the block is that it is a 2 piece rear. I dont know the year bacause I cant see the casting # on it. The transmission Im trying to use is a 1990 Borg/ Warner T-5. I know I dont have too much info for you guys to go off of but its worth a try. Thanks for any help.

diameter of shaft and spline count.
if it has 10 or 13 spline t5 its a v6 car
1 1/8 in. shaft with 26 spline is v8 t5
10.5 dia.clutch for like 3rd gens.

if u are trying to use a t5 in a 96 fbody i think u will run into some problems making it work, since them manuals in those cars are t56's behind the lt1 motors.
clutch for t56 is 26 spline with 1 1/8 shaft.
10.5 or 11 in dia. iirc

The car was originally a t-56, LT1. I bought it with no engine or trans so I installed a Gen 1 SBC and the t-5. The trans is for a V8 so its the 26 spline. But what i dont know is what flywheel/clutch combo to use with my engine and trans. The hydraulics are not the problem since they are all new and I was having the same issue when the engine was in my 90 Camaro.