Starter Motor

[motovate]

I've got a 71 chevy 3/4T 4x4 with a 300hp+ 350 crate engine. Manual Transmission with the old bell housing. It uses the old style starter that bolts horizontally into the Bell housing - 3 bolts. Does anyone know of a hight torque starter that will fit this old bell housing????? I just put a new rebuilt on and it is starting to sound rough - not like it is slipping on the teeth but like it's rattling around inside of the starter. I've got a mini high torque starter on my newer 350's and like it.; I'd like to put one on the 71 but they all look like they mount vertically not horizontally.

Thanks - LBM