Hi Ihave an 86 iroc and i need to know what size and tooth fly wheel i need. The motor that was in the car was not an 86 1 peace rear main seal so i need to find the right flywheel. thanks for any help matt

I believe its the smaller 153 tooth flywheel thats used with stock f-bodys.

since you asked about the flywheel I assume you have a manual. Only a 153 tooth will fit in the beelhousing of a t-5. But you need to get a flywheel from a 55-85 2 pc seal block. And unfortuantly they aren't cheap. $225 from summit I think. Look in the mag for 153 55-85 and thats you.

The older flywheel will not work on a 86, in all likelihood you will have a one-piece rear main seal which has a different crank flange. 86 was the first year of the new design. More likely, you need a 86-up flywheel. It will be the 12-3/4" 153-tooth type like the other post said however.

RB83L69 - You seem to be the T5 guru so let me throw this at you: I have a 86 engine going in a 85 what exactly does the flange look lik b/c it came out of my 79 Z28 but the numbers are a 86 350. I have tried 2 flywheels unsuccessfully so far and my 1 piece wheel for the 86 up is coming tomorrow will it work for me?

i don't have any pics that might show it, but the one-piece crank flange and the bolt circle on the flywheel are MUCH smaller than the older style. The crank flange itself is perfectly round on the one-piece motors since the seal rides on the outside of it, but it has a weird shape with a couple of big chunks taken out of one side of it it on the 2-piece (except for steel 265 and 283 cranks, which don't count for the purpose at hand)

a 79 Z28 motor would nostly likely be a 3970010 or 014 casting, and would definitely have the 2-piece rear main seal if it's the original engine.