How does it run at speeds?

If you let it idle after a drive, will if overflow the radiator?

If you catch what comes out, How much coolant is it?

If you don't refill it, will it overflow the next time?

How tight is the engine? can you turn it over fairly easy or does it struggle?

How many miles on it?

Newly rebuilt engine should run a bit hotter till broke in completely, rings are tight causing heat build up.

You sure you have all the air out of the block? Don't remove thermostat, it will just run hotter, most of the time. Try putting a aspirin in the thermostat to hold it open. Once the coolant fills the block and head, the aspirin will melt out and close the t-stat.

Highway driving, (over heating) is a air flow problem. How does does it cool at slow speed driving? You sure you have all the baffles and air dams around the radiator? Air will always go around something if its easier then going through it.


joe

1937 Chevrolet Inline-powered Streetrod