The GM manual transmission has had a few changes over the years. The output shafts have been 10, 27, 32 & 35. The rear bolt pattern to the tailhousing or transfer case adapter is different on most applications. The bellhousing has remained the same for the most part other then the bellhousing index to the transmission is either 4.686 and 5.125".
The links below help to identify the transmissions.
- 1. GM SM420
- 2. GM SM465
- 3. Muncie M21 & M22
- 4. Saginaw 3 & 4 Speeds
- 5. GM NV4500