1964 A body 4 speed bellhousing question.

Check on slantsix.org.

There is an article there on 4 speeds relating to /6 setups. It's been awhile since I've read it so I don't want to mis-speak.

Just checked and cut and pasted the following:

Slant Six owners have two bell housing options to mate G/RG blocks to 833s. The original 1964-66 Slant Six four speed bell housing is a great candidate and accepts any A-833 with a 4.35" IBR profile. These units were all cast iron. While these bell housings are becoming increasingly hard to come by, the inspection plate, dust shield, clutch fork, and fork boot can all be swapped-over from a Sixties G/RG with an A-903 three speed. The casting numbers for the early cast iron bell housings are 2463025, 2463027, and 2468431.