Small Block & Big Block Chevy Specific - sbc bellhousing pattern 305 - 307 - 350

have a '76 boat that has 220 hp chevy's in it, built/assembled by crusader marine. The motors are either 305 or 307 chevy blocks. One is reverse rotation. The powertrain setup is the motor, bolted to a transmission, bolted to a walther v-drive, all 1976'ish era. If i should ever decided to mess with it or it's sold, will a late model chevy vortec 350 bolt right up with the transmission and bellhousing? Is the bolt pattern the same?

Yes , all the sb chevy's use the same pattern up to the lsx engines.

Even the LS engines bolt up to the old SBC transmissions just one less bolt goes in.

And big blocks and 90 degree v-6's and straight 6's.