Water pump hose routing
 

Hi, switching a 305 tip to carbureted. Switched the intake manifold, looking at water pumps, they are the same on both motors except the water pump off the carbureted engine has two hose connections, one on top and one on bottom. The water pump on tpi engine has only the large hose connection at bottom, and the hose connection on top us plugged off.. Anyone know why??? Should I just remove the plug and put the hose fitting on there? I don't understand why one is plugged and the other one isn't. Any help would be much appreciated

Re: Water pump hose routing
 

Hot water going TO the heater comes out of the intake. You have no choice in this matter: hot water comes out the top of the motor.

Cold water coming back FROM the heater has to go to the cold side of the cooling system. There are 2 commonly used places to access this spot. The fitting on top of the WP, and, the nipple made onto the cold tank of the radiator.

Either will work fine. They are identical as far as water flow and function are concerned. You can use either. Use whichever fits better with your preferred hose routing and plug the other. Use a pipe plug in the WP if you decide to hook the hose to the rad, and a "cap" over the rad fitting if you decide to use the WP.

Until the mid-late 80s, there was no fitting in the rad. The WP fitting was the only one that existed. Nowadays, to make every replacement rad fit as many applications as possible, they put the fitting in every replacement rad. Cap it if you don't want to use it.