[68gmsee]

I did a little searching since your question got my interest. I have the same engine and transmission and have kicked the idea of installing a 4 speed on mine. Here's something of what I found on this site and this article which may or may not help: http://www.customclassictrucks.com/t..._transmission/

GM called it both A833OD and NP440. The RPO # was MY6. There were two types of the trans installed in the trucks from 81-86. One had the same bolt pattern as any Muncie, BW, or Saginaw and would bolt up to a standard GM bellhousing if you turn down the bearing cover. This is the one I have and it's bolted to a '621' bellhousing. The other had a specific bellhousing because the bolt pattern. It looked like the one on the left in this pic.