1964-1972 / , 1967-1969 , 1968-1974 , 1966-74 , 70-73 Flywheel Inspection Cover. Bolts to the aluminum bell housing. 11" inspection cover for all models. Comes black powder coated. Hole measures approximately 2 3/4". Fits the 11" 3899621 bell housing issued on all / / / / with big block 396 / / 454 Yenko / Copo / ZL1 and also small block like 302 / 350 or with 11" clutch; Z28 / Yenko / Deuce models. Fits most 1964-81 except for 1962-67 . 4 speed only 11inch Clutch GM Motors.