Water pump to big

The early pump is shorter as kimmer says, but it is not a match for your later 360. You'll probably need new accessory brackets to go along and possibly even the early timing cover to get things "right". I believe the better fix "HERE" will be a thinner two row radiator. A good two row with two rows of wide tubes will very likely cool better anyway. Can you post some pictures? Most of the aftermarket imported radiators have the brackets welded on offset so that they mount the radiator closer to the engine than need be, PLUS the 3 row radiator itself is just slap too thick for this application. There are probably a thousand threads on this on this forum alone.