Flywheel Size / Bellhousing Question
You have to understand that a larger/ smaller flywheel has to "move the starter." This means that there is no way to use the smaller wheel in a larger bell
So far as 10.5 --11", there ARE 11" clutches that use the 10.5 cover bolt pattern. These are variously referred to as "scalloped," 10.9, 10 7/8, and 11"
You can identify the originals by seeing the disc lying in the upturned cover. The cover has mounting ears that come UNcomfortably close to the disk
To my knowledge, these were first used in things like the 70 B bodies. My 69 383 RR had a "real" 11" clutch, while my '70 440-6 car used one of these "fakes."
Here:
http://www.forabodiesonly.com/mopar/showthread.php?p=1969798974