I have a 1968 mustang coupe with a rebuilt 390 motor with the cylinders are bored out to 60 over and my problem is the motor runs hot, if I drive and not stop it goes up to 210 degrees, but if I start to stop and go frequently it will go up to 230 degrees, I took out the thermostat and have a electric fan in front of the radiator that covers 3/4 of the surface, what is the highest temperature can the car go without it to overheat or get bad, it is a rebuilt motor, will that make it run hot, and if I put a fan shroud and a fan and put the electric fan on the outside, will this make it run cooler, if anyone can answer this I would really appreciate it, thanks peteman

 

welcome!

 

I'm Plaining on putting an electric fan on the outside of my radiator, so it will run cooler along with the fan on the engine. So it will run cooler!! On my 65

 

Welcome, you need to asks the guys in the Classic section. I know they will have some ideas and can point you in the right direction. Have you checked to make sure you have all the air out of the cooling system? You said you added an electric fan, is this in addtion to the clutch fan? Is the clutch bad?

 

Are you sure that the electric fan blades are configured correctly to push air rather than pull. Also, the electric fan motor rotation has to be set to push. If these both are not correct, then you're fighting the direction you want the fresh air to go.

 

what size engine do you have, I have a 390 motor and had a electric fan on the inside and it was running hot, 220 degrees and I put a clutch fan and shroud and about 78 degree weather, it got up to210 degrees, but on a hot and humid day 90 + day it went up to 230 degrees and drove it home and while it was running, I sprayed cold water from the water hose into the radiator and it dropped down under 190 degrees, this is what I came across on my 68 mustang with a 390, you must have a 289 or 302 because they didn't put big block motors until 67 mustangs, I went to car shows and seen a electric fan on the outside of the radiator, not a big one and some do not have one but it would not hurt, let me know if that works, because I have to do something like that, but with a 390 motor.

 

I had the fan on the inside between the water pump and radiator and the fan was pushing in