Whats up I put a 235 in a 51 sedan ... The motor was said to not overheat ...The last thing i need to check is the water pump, what am i looking for if this thing is bad or good ....
So it's boiling over and acting like a geyser... or your gauge is just telling you that it's hot? I swapped engines once and spent an ass load of money on a huge radiator and a multi-blade fan only to find out that the new engine sending unit was giving false readings to my gauge. I did not have an overheating problem at all. I just thought I did. An infrared remote sensing thermometer is cheap and very helpful for trouble shooting a cooling system. You can locate clogged radiator tubes etc. and check the reading of your gauge. I learned the hard way that it can be very expensive to guess at a problem and throw new parts at it trying to fix it.
I put a used waterpump from a '55 Chevy on my 235 to replace one that the bearings were shot in, it wobbled and was leaking through the front. The used one came off a junker that had sat for years with no front clip on it. It was fine. If it's not leaking out somewhere, yours is probably fine too, the only thing that could go wrong that you wouldn't be able to see is if it's a cheap rebuild and the impeller's not pressed on tight so it can spin on the shaft. Take the thermostat right out and put it together, you can rule that in or out as the problem in a hurry at no cost.
Dont know about your engine but alot of vintage engines I have come across ,the water jackets in the block have been almost completely clogged by years and years of mud and crud . Have had two 331 caddys that were this way. If water can't flow around all the cylanders it will run hotter than normal , If not flat out overheat. Just something else to check.
If it sat any time outside a vehicle with the water pump and thermostat open critters could get in the motor and make nests.
As Tommy asked why do you believe it is running hot? Is the gauge reading higher than you think it should? Is it puking water/coolant? Or??? I like Tommy's suggestion of using an infrared temp gun/gauge to check. One of the better 30 bucks I have spent for trouble shooting heat related issues. But back to the problem. Did you flush out the radiator and make sure you have a good flow going through it? Are there any kinks in the upper or lower hose that might be blocking coolant flow? Does the thermostat work? If you take it out and put in a pan of water on the stove will it open up? With the cap off can you tell if the pump is moving coolant in the system? Also some of these engines/cooling systems need to have trapped air burped out of them and can act up if all the air isn't out of the system and the system is full of coolant.
Its puking out of the radiator ..... Boiling over ..... I checked the thermostat old one was stuck open when i removed it and the nev one is working fine .. even jacked the front u and ran without cap on thinking it was air in the system .. The only thing left is the radiator
Before replacing/reparing the radiator do a "block check" to make sure you di not havea combustion gas leak into the cooling system. Most radiator shops can do this and I think Auto Zone rents/loans them. You may have a bad head gasket or a cracked head as old Chevys were prone to do.