Early pumps exit on the drivers side for the lower radiator hose
Late pumps exit to the passenger side
Question is, where is the lower hose fitting on your radiator?
The Hayden short shaft clutch fan mentioned above is readily available and a real problem solver and not too pricey.
The early and late pumps also have different placement of the timing marks, so if the donor engine is a 74 and you are using the original harmonic balancer, the timing mark would be WAAAY off if used with an early pump.