Running hot at idle

[Scubaman]

Had my ‘73 convertible in the shop about year ago for a 10 year complete going over. Oil pan was leaking, oil, spark plugs, filters, replaced all hoses, fixed rim blow horn, etc.
since then the 351 Cleveland runs hot at idle and cools down when running. Higher rpms generally much cooler. I have read that the thermostat may be the issue and the shop may have switched it when they replaced the hoses,
My research has indicated that I may need a high flow Robert Shaw thermostat. Can anyone confirm that this may be the issue. And if so can you point me to where I can get the proper thermostat? Thanks Stan

 

[Sheriff41]

The thermostat could be the issue and the 351C does take a different style thermostat than other small block Ford engines. Also, make sure the bypass plate (not sure the correct name) is in place. The thermostat and the plate work together for the cooling system to function properly.

Also, if your car has a fan clutch, make sure it is in good condition. If it is slipping too much at idle it can lead to overheating. If you can easily spin the fan by hand (with the engine OFF, of course!) then it may be suspect. You should be able to turn the fan by hand but will feel the resistance from the clutch.

BTW, nice looking convertible!