A904 to 360

You can use your '64 transmission complete if you use the special flex plate that B&M makes for an externally balanced 360. The only other item you need is a bushing to go into the end of the crank so you can use the small button convertor that your '64 has. All good used convertors have a stall speed........some are just higher than others. If you need something higher than the '64, you'll need to have one made. The A100 should have a 727 and the convertor from one of those won't fit a 904.