It appears that the Wilcap 600WA adapts the early flathead transmission to the Y-block
https://picclick.com/Wilcap-600-WA-F...750850030.html
I believe all the ford car transmissions were the same bolt pattern to the bell housing up to 1964, I think. Some pickup bell housings had motor mounts cast into them. Heavy truck might have had different transmission bolt patterns, I don't know.