I had/have a similar interest in an eventual diesel re-power of my 50 3600 pickup. I joined the cummins4BT yahoo
group . Even though it is mainly for 4BT (3.9) 4-cylinder cummins there is lots of info on the 6BT (5.9) 6-cylinder motor. Your SM-465 4-speed is found behind a lot of 4BT cummins in step/box vans. Frito Lay has auctioned off hundreds of them. The bell housing will work in all/most/some 6BT applications. There is also a guy on the oldgmctrucks.com forums who put a 5.9 cummins in a 49 or 50 Chevy 1-ton pickup. Good Luck! and keep us posted.
