What year 3600, Don?
"I have a 3600 with a sm420, torque tube, drive shaft to the rear end."
Do you have a torque-tube and enclosed drive shaft that runs all the way to the rear end, or a torque-tube for a shot distance behind the transmission, and then an open drive-shaft to the original 3/4 rear end (what year)?
I looked back through your posts and I think you might be referring to a 1949 3600?
It has an open driveshaft into the rear end - right?
http://chevy.oldcarmanualproject.com/chevyresto/4973.htm
