It depends on which year 383 your wanting the flywheel to fit on properly with the bell housing, pre 1967 I think they only offered 10.5 clutches in passenger cars, beginning in 1968 I think they started offering the H.,D. 11 inch clutches on the 143 tooth flywheels and matching bell housings
Mopar change all the V8 cranks in 1962 and up to 6 bolts flanges(except the 426 hemi 8 bolt motors) and moved the flywheel closer to the back of the blocks and switch the gear drive starters at the same time.
IHTHs