So my buddy wants to go 4spd on his 72 Cutlass. He says his 455 has a stick crank behind the Turbo 400 and has all the parts for the swap. Everything comes apart well. We go to put the stock pilot bearing in and its a no go. The bearing is slightly too big and the crank is drilled but not to the correct size. So I had the bushing type adapter on hand which we installed but then the fun began. The trans would not go all the way in it was about 1/2" out we tried and tried and realigned the disc a few times but no go. Turns out the adapter bushing stuck out too far and would not allow the trans to go in far enough. The adapter was all the way in. The splined part of input shaft was hitting the bushing. We took measurements to confirm. I never heard of this issue before. I recently used the same adapter on another 455 but with a Lakewood bell housing and there wasn't an issue. We ended up shaving the stock bearing a bit and got it in the crank where it belongs and the trans slid right in. This is not my 1st rodeo. Was wondering if anyone else had a similar issue?

 

It happened to me as well.

Hopefully, you will be able to shift into reverse, as the input shaft hits the adapter and does not allow the input shaft to float when the clutch pedal is depressed.

I ended up pulling the engine, and having the crank drilled for the BCA7109 bearing.

Has worked flawlessly since.

 

Good info, I am surprised though I haven't heard of this issue before, although seeing where that adapter bushing sits in the crank I always thought it was a real possibility.