There is two SM465's?? The one with 1 1/8 input from one ton trucks and one with 1 1/2 input from 23000 gvw and larger trucks.
Other than the input shaft and bearing retainer size what is differnt? Is the BH bolt pattern to trans the same? Is it just that one bottom bolt.What about the shaft stick out?
What I am getting at is will the big SM 465 bolt up to the small bellhousing and will the input shaft work? Thanks for your input  

As they ship from factory, BB and SB SUV's and 4x4's used same bellhousing and tranny when a 465 was involved. I can not say what difference might be in a 26K GVW application but I can say what it is in all LD applications and yes, even a 1 ton P/U with a BB is considered a LD truck in the the truck world.