273 Waterpump/Radiator Swap....Help

I agree with Commando.... changing to the newer style water pump will necessitate changing a number of other things and should be considered in your decision to do the swap. You will need the later style alternator brackets, the correct power steering pump brackets for your style of pump, at least the water pump pulley and maybe the lower crank pulley also. Don't be surprised if you need to run a double pulley alternator also, as the single pulley is for the earlier cars with your old setup. These are all possibilities, but not necessaryily probable, and this will become more apparent as you mock up the new water pump. Good luck with your project, Geof