In general a well tuned engine is necessary for proper reliability and temperature.
As to cooling in general:
Most of the complaints I hear of are at low speeds in traffic or use in parades. In this use the car moves slowly and at relatively low r.p.m.s. The result is higher than desired engine temperatures from less than optimal air flowing through the
radiator for adequate cooling. The use of a "parade fan" is desirable for this to increase air flow through the
radiator allowing adequate coolant temperature reduction.
Things I have discovered as contributing to running hot include, but are not limited to;
Incorrect timing; if the engine has many miles the timing chain may stretch. Timing with a light is then inaccurate. To correct for this I suggest use of a
vacuum gauge for timing.
Faulty vacuum advance. I have observed many cases of the diaphragm being torn, punctured ot otherwise worn out. The result being inadequate advance.
Build-up of sediment in the block that creates hot spots and poor coolant circulation.
Faulty
radiator cap, they do wear out.
Faulty thermostat or wrong temperature choice for the thermostat.
Radiator clogs. Use of a
radiator that over time flows less water than needed for cooling.
Along with this can be a
radiator of insufficient core size. In general a 4 core in a steel/brass-copper
radiator is adequate.
If you have a 55 with the 3 blade fan, not generally adequate. The later 4 blade fan may also be inadequate for air flow through the
radiator at parade or heavy traffic speeds.
I see a modern consensus of:
Non stock fans of at least 6 blade flex fans.
Along with this I recommend the use of an aftermarket lower shroud that covers the two lower corners of the
radiator. The stock semi-circular lower shroud does not draw air through the two lower corners of the
radiator.
A thermostat of a rating of 180 degrees should be satisfactory. Additionally drilling a 1/8" hole at the top of the flat portion of the thermostat to allow "burping" of the air out of the cooling system.
As a final caveat, you may need more initial advance for successful temperature control of the engine.
