The correct pulley for a 1955-62 235 is about 7" in diameter.
The most common problem running your setup is thrown fans. Running at the faster speeds the fan flexes more than designed for and will crack and break.
I am glad you posted this fact. My pulley is about 4 1/4" diameter and I am convinced it is too fast, fan makes a lot of noise. (Engine is 1960 261) Thanks.
