[Fullraceflathead]

I have a crack in my AA four-speed bell housing. I carefully cleaned the housing, followed the end of the crack and drilled the hole to prevent it from spreading. I believe mine was probably cracked from an accident from a previous owner. The bell housing was in near mint condition, which surprised me to find a crack. There’s virtually no wear in the bushings or on the clutch fork.
As long as you drill a hole at the end of the crack to prevent it from spreading.
I would not hesitate using it. You can see the crack in mine is much worse than the crack you have. The AA four-speed transmission is probably three times as heavy as the original three speed transmission.