Topic: 68 mustang with a 87 302 overheats

[kfickle1]

I have an 87 rebuilt 302 in my 68 mustang. I made sure the head gaskets are on right. The timing is set. I have ran it with a 190, 160 and no thermostat. It still overheats in about twenty minutes. The radiator is a 3 row, which is new. The water pump is new. The radiator hoses are new and the bottom hose is not collapsing. One of my questions are the mid 80's the 302's have reverse water pumps, I had to change the timing cover with an older one so the fuel pump could be added, I also replaced with an early 80's pump. Would this cause an issue? I am going to try a smaller water pump pulley to see if that works. The fan is pulling air through the radiator.
Any suggestions? 
Thanks,
Ken   

[Soaring]

A couple of things.  The thermostat should be a 180.  You may have the wrong water pump on it.  The water pump sucks water from the lower hose, pushes it into the block, and it eventually comes back out the top of the intake at the t-stat housing and dumps back into the top of the radiator.

Once your thermostat opens, your lower hose will always be cooler than the upper hose, as that's the cooler water coming back out, and the upper hose is the hot water coming out of the engine.

If this is all correct, then get yourself a shroud, a 6 blade fan and a recovery tank. 

[willyod]

I have had issues like this several times. On two occasions it was the mis-matched fan to shroud( like was using a flex fan when I needed a clutch for stop and go), and the last time, believe it or not- the water was passing through system too fast, did not have time to cool. I restricted the flow to confirm it.

[Soaring]

Are you saying you think the kind of fan has something to do with the flow rate of the coolant?  Hmmmmmm

[willyod]

Not sure which was happening, either the fan was not pulling enough air because of the shroud, OR the coolant was passing through the radiator too fast because it was a 3 core. I know its not logical but that is what it was. As soon as I restricted the flow it started cooling. Must've been because the fan wasn't pulling enough. Some people try to use the stiff racing flex fans, they are not enough for stop & go. I always try to use the largest diameter true flex fan the shroud will allow. Such as one off the mid 70s and up

[Soaring]

The fan was pulling more air across the rad because of the shroud, not the other way around.