Cooling Issue - 1964 Dart GT - 273 with automatic and A/C

RustyRatRod said
That's the correct width radiator for an early V8 car. I recommend a high flow 160 thermostat. May or may not help, but it sure won't hurt. Also, measure your crank pulley and water pump pulley diameter. Your water pump pulley should be smaller than the crank pulley so that it is overdriven. If it's not, that could certainly cause some of your low speed heating issues.

Thanks for this info. I looked at the two pulleys, and they appear to be roughly the same size, about 6-5/8". Any recommendation on size, and a vendor? I looked at Classic Industries and they only have the 6-5/8 pulley. They have the 160 high flow stat, so I'll get one of those.