[Born30YrsLate]

Last fall I picked up what looked like a muncie M22 tranny - it has the course spline input shaft with no rings on the input shaft and a 661 case, I'm thinking it was a warranty replacement trans - it also has no VIN on the case as well as no assembly date. Recently I took the side cover off and the cut of the gears resemble an M21/M20 (gears have a steep cut to them)...I compared them to a '68 M22 I have and there is a definite difference in the angle of the gears in each trans (the '68 gears are at about half the angle as the other trans I picked up). I had initially thought that maybe somebody stuck and early set of M20 gears in the trans, but didn't they use a different size countershaft back then. I am confused why there are no grooves on this input shaft (indicating an M22) but the gear cut is the M21/M20 style.
As always - all input is appreciated.