[poncho-mike]

I've owned a couple of 1972 Trans Am 4-spds over the years. As others have said, the M22 is very noisy. I've also owned a couple of cars with Muncies where the countershaft bearings were going bad. They have a combination of whine and roar. An M22 in good shape will produce an annoying whine, but a M22 with a bad internal bearing is obnoxious. Post the last couple of digits of the VIN, the correct block may still be out there. BTW, a 1972 T/A could come either with a distributor (WD code, I think) or a WM (electronic distributor).

I have a WM out of a Firebird that is a little too close to the build date for my car. I've been looking a block with a cast date around January 1972 for it, the cast date on the block I have is B292 (leap day). I am undecided if I want to use a service block or a WM that is too close to the production date.