I dont know to just about all your questions. Only known is that the R-11's are the stout units. I do have some chevy parts books that will have GM part numbers for the R-10 pieces. but I would not want to waste too much money or time on the R-10 units- I had one and let o/d cavity run dry. The planetary gears turned blue and stripped themselves of teeth and finally locked up the tail shaft and parked me in the middle of rush hour traffic, but for the 2.94 low gear and the old 261's torque we just manhandled the rest of what was left onto the side of the road. When we looked under the pick up, the old oil on the side of the tranny case was bubbling and smoking! After work and a trip home another crashbox was put in and driven home ( thank goodness for spares).
