That is exactly what Jerry was referring too. Once the engine comes up to temperature, the coolant expands purging out any excess coolant. After it cools, you will only see coolant just above the cooling fins. Some put on an expansion tank to remedy this.
I have the same setup as you, only on a 235 and don’t experience your issue. I had my engine boiled out as well as the original radiator when it was rebuilt, run a 180° thermostat (also drilled with a 1\8” hole) and a 4 lb. radiator cap.
If it continues to overheat, in traffic, you’ll need to look elsewhere.
Last edited by Phak1; 06/10/2025 11:20 AM. Reason: Typo
