Jerry, the Saginaw 4spd was first used in Camaros and Chevelles, for sure in 1968, maybe 67. Never used behind a big block, but was common with 275hp 327's and early 350's and in other GM models . 66-69 Corvair 3 spd and 4 spds,the gearsets were indentical in size and design to the Saginaw, some parts were interchangable.The 3 spd version,which used the same mainshaft, case and gears, appeared in 66 GM trucks and some cars.
The Saginaw is ok for street use in a moderate V-8,it's a lot cheaper than a Muncie and not all that much weaker in reality.I personally knew a few guys back then who drove hard and had no problems.Saginaw 3 spds are also used dirt circle racing low buck classes
I'm no Vega expert,but from some quick research, I believe the Saginaw first appeared around 1973 , 2 years after the car was introduced.It appears the 71 and 72 Vega used a GM German transmission from Opel.
