I had a 1963 C10 Longbed Fleetside. It started life with a 283SBC/Powerglide combination, but went through several combinations and finally was sold with a 400SBC/TH400.
I hated to see that old truck go, but I was getting married and needed money more than 2 trucks and 2 bikes.. That's why 18 years later, I got my 1962 C10 Shortbed Stepside.