I have ran an 250/mild cam/header/clifford intake/4bbl carb with a standard S10 5sp for years in my 1952 1/2 ton. It worked well for years. Then six finally died and now run a SB305 (Shame) and the same 5speed. It's even the weeker 5speed, that came from an S10 4 cly (Lower 1st gear).
Dave
Chico, TX