[Jack21]

Don't take this 5 bolt vs 6 bolt bellhousing issue lightly, or you'll be all dressed up with noplace to go.

Ford (in its infinite wisdom) used a 5 bolt bellhousing in their 221's, 260's, and early 289's. They mated to BW T-10 4 speeds. In the '65 1/2 or '66 model year, Ford switched to a 6 bolt bellhousing which is consistent with the 289, 302, and 351 from '66 on.

You can use your '64 block IF you have matching bellhousing and T-10 trans. Otherwise, scrounge up a '66 or later block. (Or use a 302 block, and put a 289 crank in it).

Guys trying to upgrade their '64 Falcon Sprints, and Comet Cyclones found this out the hard way.