the 3 speed wil be fine seeing you already have the shift setup, why bother choppin a hole in the floor for a 4spd that still has 1:1 top gear? - bellhousing from standrard trans SBC 55 on for many years - can use the original style front mounts [repro from any supplier] or add a cross member to take the usual SB side mounts - original driveshaft - fan shroud to take care of the V8 being way back from the rad - drive it
Bill