Thanks HFR, still a lot I don't know about the '73 TA.
I spent a fair bit of time searching the archives. Not a whole lot of help either way.
Found nobody that has claimed to have an original drivetrain base '73 TA with the M20.
I've been contemplating why PMD may have offered both but haven't come up with any good ideas. And why put the M20 in the SD if the base TA was getting the M21?
I'm 98% sure mine had the original trans in it when I owned it in '78. But there is no way I believe I could have sensed the difference between an M20 and an M21 so that is a dead end.
dadsformula, you stated that "nearly all of them were M21 Muncies", referring to the 227 '73 Formulas with 4 spd and L75 455. Does this mean you know of documented '73 Formulas that got the M20 with the 455?
Based on what I know about the usage of the M21 in the '64 GTO and the fact that a LOT of '64 guys thought they had an M21 in their original drivetrain '64s that invariably proved to be an M20 (when the M20 was a 2.56 1st to boot) and I'm convinced very few could detect the difference from just driving.
So unless somebody out there steps up with proof of a base '73 TA with the M20, I'm resigned to the idea that the M21 was the likely base '73 TA 4 spd.
Makes the '73 M20 I picked up not quite the prize I thought it was.
