Also remember there is two different water pump housing that pump on the left side and right side for the outlet. not sure but it may also make a difference what pump you have.. it does make a difference which way those propellers turn..

Also I see you have a 69 440 pump, don't know the other one's year make, I bought one that was round like the one you have and couldn't get the belts to line up until I noticed the difference in the thickness of the metal where the fan belts go in,,, it threw me off and had to put the correct one on...

Facts: Both pumps/impellers turn clockwise -
The pump on the right definitely was in the engine when overheating.
The pump on the left is a NON ac and the impellers are opposite the pump on the right. Does that matter?
I ordered an AC pump (thinking it made no diff) that is
installed now and still overheated. So I took the thermostat
out and now runs cool 170 deg.

Do ya think installing the left pump non ac will make any difference?

The size of the pulleys is different. A/C pulley is smaller than the non a/c.If you use the wrong combo it will drive the pump at the wrong speed and cause cooling prolems or cavitate the pump. John.

So if I'm running an A/C water pump with all else being non ac
will that cause overheating condition.
Thanks

Actually,the original a/C pump is 6 blade ! When you order an A/C pump you get one size fits all 8 blade.

Have you tested the stat in a pot of boiling water? It sounds like you just got a bum stat. You might also look for a high flow stat. Those have bigger open areas for more flow. Robershaw used to make some, havent seen them for sale in a long time though.

I'll help out by posting the info again:

Number one, beyond any question, is to get a temp gun. Period. End of sentence.


Harbor Freight has them on sale for $37.
http://www.harborfreight.com/infrared-thermometer-with-laser-targeting-non-contact-69465.html

Those things work great. Sure, they may be off a degree or two but who cares? You're looking for big swings in temperature and they will get the job done.

If you don't have one you obviously don't want to know why your car is overheating. Get one. Now. We'll wait for you. This thread should still be around when you get back from the store.
Don't have overheating problems? Go get one anyway.

If you have real temperatures of different parts of the cooling system it's really easy to track down any problems. Without those temps you're just guessing.

Use the temp gun to check the radiator temperatures. if your cooling system is working properly you will have about a 30 degree difference between the radiator inlet and outlet. If that isn't the case you have a problem up front.

Scan the radiator across the core. If there are cold spots you know the radiator is plugged and needs attention. Obviously, the radiator will be cooler where the fan is drawing air. If the fan clutch is slipping or the fan is too weak then you will not see a substantial drop in temperature in front of the fan.
Here's a BIG hint: A proper shroud will pull air from all parts of the radiator, not just the bit right in front of the fan. That's why shrouds are important.

You can use the temp gun on the temperature sending unit to confirm the gauge reading.
It can also spot colder spots on the engine if you have a misfire or dead hole. The temp will be cooler on that part of the exhaust manifold too.
You can shoot the cylinder heads to see if one side is cooler than the other. That would indicate problems inside the engine.
Trouble with the A/C? You can check air temperatures at the registers as well as line temperatures under the hood.
Don't have a candy thermometer? You can use the temp gun to monitor you cooking oil when frying hush puppies.

Back to trouble shooting...

If the temperature of the hoses is drastically lower than the temperature of the block and heads then you're not moving water. Check the lower hose to make sure it's not getting sucked closed when the engine is revved. Sometimes it's hard to see so you need to lay hands on it. Just don't get your arm caught in the belts or fan.

If the upper hose is drastically cooler than the thermostat housing and top of the water pump you know the thermostat isn't opening.
Engines without thermostats will sometimes move coolant too quickly. That doesn't allow the coolant to stay in the radiator long enough to lose temperature. You can spot that when the radiator temps drop smoothly across the radiator but don't change by more than 15 degrees or so.

If you want to know why something doesn't work you need to find out what part isn't working. When that's a cooling system you must know the temperatures you're dealing with. Without that basic info it's all guesswork.

Have a problem? Want help?
1) Get a temp gun.
2) Get numbers.
3) Get back with us.

Are you sure if engine was machined and assembled with correct clearance?
If it's tight, temperature goes up.

Carburetor is no lean? If it's lean, temperature goes up.

Since it runs at 170, why not let the next guy deal with it? It is a flip afterall.

Feets helped me through my over heating problem on my 1969 RR. The IR temp gun makes a night or day difference and have since used it on other things. WELL WORTH IT!!!! Mine was a radiator but ran hot even with no stat. but I took all the readings at different times on different days and checked each cyl. temp just to make sure. There is also a test kit to check for combustion gas in your cooling system, also a great thing to have around.

If no stat SOLVES the overheating then k.i.s.s. you had the misfortune of having 2 bad stats in a row (the one that was in there went bad & the new one you bought). As said you might test a new one suspended in a pot of water & bring it to a boil (candy thermometers are cheap) & dont forget the temp gun . I push the stat open several times by hand to make sure it is free/not stuck before I check it on the stove. Holler how it turns out

Question on a big block can you reverse the intake gasket and block off the coolant passage i have seen that happen on other makes??

I'm going shooting today...

thank you