[bigblockv6]

The 478 has to have a flywheel with a 8 mounting holes to the crankshaft and have external balancing. This flywheel is common to 379, 432 and 478 engines only. 305 & 351 engines only have a 6 bolt flywheel. Some 401 engines have the 8 bolt flywheel but are internally balanced so this flywheel will throw your 478 off balance. Freeze plugs are the same from 305 through 478 engines.