That cross member might work...depending on what transmission are you going to use? You also might have to remove the existing bell housing cross member and then fabricate a new one as that cross member also stabilizes the frame at the spring hanger.
The easiest swap might be a 350 SBC and keep the existing transmission...all you would need would be a V8 bell housing, V8 throttle linkage and V8 front motor mounts. The SBC can handle higher rpm so the truck can run faster.
Mike B
