Hello, I'm desperate for info. I have a 3 speed manual tranny that I took out of my racecar. It has gm casting numbers on it.

side cover: 3731911
housing: 3845122
tail housing: 3707185

I have been searching the net and haven't been able to find anything. I saw an article that says the housing is an early saginaw, but when I called drivetrain.com, they said it was an early muncie. I'm lost!

Please help. Thanks, Matt

Saginaw would be a cast iron case and a Muncie would probably be a aluminum case.

Most Saginaws will have either one or two or three rings across the input shaft and you can usually tell which gear ratio'* are inside by the amount of rings - but not always.

SAGINAW 3-SPEEDS (CAST IRON)

0 LINE INPUT -2.85/1.68/1.00

1 LINE INPUT - 2.54/1.50/1.00

2 LINE INPUT - 3.11/1.84/1.00

3 LINE INPUT - 3.50/1.89/1.00

The internet says that your transmission is a 1950 - 1960 3 Speed Saginaw and was put in a 1957 Corvette / Passenger car.

There would be a date code somewhere stamped into the casting that would give the actual build date.