I currently have what i believe is an SM420 - 4 speed behind the 350.

i'd like to have a 5 speed, but pull a boat and a trailer, so i like a low 1st gear - which leads to my question -

any one try a later model 5 speed out of a 3/4 chev? if so, what little stuff did you run into?

The big picture
1958 Chevrolet Stepside in the Gallery
Photobucket album