I picked up a 26 spline S10 WC T-5 off craigslist today.
A while ago I read a great thread on swapping a T-5 in place of a SM420 on a 305e. Now I cant find it.

There is a good thread on T-5 on the 67-72 Chevy Trucks Forum in the 60-66 section.
Swapping manuals transmissions are a bit alien to me. All of my previous experience was auto trannys. I already had an original auto trans adapter for my 305e and was going to go to a 700r4 when I found the T-5. I'd rather keep the original look on a manual trans in my truck. With a OD I can keep my rear gearing and drive on the highway.
Winding out at 50 made for some long rides to work.