I had a 72 GTO, M-20 Muncie and it had the big TH400 yoke. I didn't know you got a Saginaw 3 spd, in the Firebird in 72, but I guess it probably would have a small output shaft. As for the bellhousing, like Joe said, I would "think" it would be the same. But with general motors, you never know what you get. I'm sure the bolt patterns for the block, and tranny are the same. And of course, the depth for the input shaft should be the same too. And lastly, I would "expect", the pilot hole diameter for the frt brg retainer to be the same. But never had one to compare. Good luck with the swap. It'll be worth it.
