[Tom Kirkham]

Kris,
We have had some flywheels that would not take the larger 11 and 1/2 inch clutch. I believe that the 390 flywheels were not drilled for the big clutch.

2. 390 and 427 are both internally balanced and take a neutral balance flywheel. The 428 is externally balanced.

3. McCleod flywheel and clutch. We are also very happy with the Center Force dual friction clutch. The stock 390 flywheel is cast iron. It is NOT the hot set up. Just think about where the flywheel will go if it explodes. The 427 had a steel flywheel from the factory. I much prefer the McCleod aluminum flywheel. Also be carefull as some of the Hayes and Weber flywheels only have the steel friction liner out to 11 inches and not the full 11 1/2. I would highly recomend the 11 1/2 clutch.
Good luck
Also in a similar vane the 390 truck bellhousing and the passenger car bellhousing are not the same depth. The truck bellhousing is about 1/2 inch deeper. The Lakewood scatter shield is the passenger car depth. Also when using the Lakewood and any other bellhousing it is HIGHLY advisable to check and make sure that the bell housing is concentric with the crankshaft.