Thanks for the info - I have just bought the Mercury and trying to get to grips with everything. It currently runs within the range you have suggested so thats good

"Correct" is a fairly flexible term. No expert, but if you want max. heater performance, longevity, and efficiency, and your cooling system is adequate and in good shape, I'm guessing 190-200 degrees minimum?

I currently have a 170 degree thermostat and a clean radiator. On a cold day, though it pulls like a freight train, no way I could run around with the top down. Heater IS adequate otherwise though.

Originals were 160 degrees, but Ford soon went to a 180 for replacement in cooler climates.

Maximum power is another story. Excessive heat expansion equals power-robbing friction. Not my field of expertise, but I think that once the rings are expanded just enough to seal, higher temps are a detriment (?) to racers.

6 VOLTS/POS. GRD. NW INDIANA

Hi

I have a 54 Mercury Monterey with 1956 312 Y Block - can anyone please tell me the correct operating temperature range

Many thanks in advance

Jazzer