New Ford 351 overheating

Old 07-27-2020, 03:58 PM
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Default New Ford 351 overheating

New Ford 351 with GT40 heads

The impellor is new and the pump is pumping water, (Sherwood pump G-21 or G21)
The impellor has been installed twice to ensure that it was oriented correctly. I also disconnected pump outlet while running to verify the flow. The flow of a water was similar to that of a water hose at idle. Not sure how to check if the flow is enough.
The cooling system has been primed.
The exhaust system is new (risers, elbows, even hoses)
Even installed spring in coolant hose to ensure that it wasn't bent or reducing flow,
The heat exchanger has been cleaned and acid dipped, it is original but looks to be in good condition and doesn't leak
The thermostat has been removed for testing only
The strainer has been cleaned
The risers are hot to touch
The belt to the water pump is tight.
The engine will start to run hot sitting in the water at the dock idling.
I would think at idle in the water without a thermostat that it would be extremely difficult to overheat.
The ignition coil is cool to touch

The only thing that I can think of trying at this point is seeing if it overheats on the garden hose while in the water and checking the transmission oil cooler. It did not seem to overheat on a garden hose before while on the trailer.

The engine sounds stout, it sounds like a fox body mustang with the exhaust.

If someone can tell me how to check if the flow of the system is adequate that would be great.

Please don't derail things over the thermostat it will be re-installed once I figure things out. (Fully understand the purpose of the thermostat)

Is anyone running a stainless steel or titauium heat exchanger, I fairly certain that my heat exchanger isn't the issue but I would like to get a permanent solution as everything else on the motor is new?


Thanks, for any and all help

Last edited by deshet; 07-27-2020 at 04:33 PM.

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