Thanks for the confirmation - I really thought so but...
Were there any outliers or exceptions through any and all generations?
Early L6 (216 and 235 engines) were different. V8 pattern lasted from '55 to '93, with the introduction of the 5 speed manual transmission. Trans patterns stretched from really early (my '49 has the same trans bolt pattern as Saginaw and Muncies) to '93 as well, although the two lower bolts of the trans are threaded into the trans, not the bellhousing, which continued for a good length of time on truck transmissions. You can bolt a Muncie to the '49 using nuts on the inside of the bellhousing for the two lower holes.
One bit of trans swap trivia - I bolted a '65 Muncie 4 spd in place of my '57 Bel Air's long tailshaft 3 speed (original non-synchro 1st gear) trans in '71. Used the original driveshaft with no mods, Input shafts are the same on all of them for length, the tooth count changed to a fine spline in '70 (and 400 output shaft diameter). Bolted the same long tailshaft '57 trans into my dad's '49 3100 3 window and hooked it to the column shifter using the same linkage from the '49, after pulling the old torque tube driveline out. You gotta love commonality/interchangeability among GM parts -
Regards,
Steve