2000 miles on a new 290 h.p. crate motor with new distributer/ wires/ plugs/ shorty headers/ taller intake/ Rochester carb with 3x14"/: filter /battery/ starter/ temp and oil pressure sensors and ( yes I trust the gauges) flushed and tested 2 row aluminum radiator with Evans coolant/ and a190 degree thermostat. she ran very hot until I got the air out of the block...but...now that it's cooled down here in Detroit it won't climb past 140 even with half the radiator covered over. coming of the highway we climb back to 185 for a while but driving around town it's back down to 140. owned this car for 23 years and sometimes think fondly of that normal and easy going 305. thanks guys for any ideas. spenc

 

If it's a fail safe thermostat it may stick open when overheated. You may have to replace it.

GD

 

You not running any water with the evans coolant correct?

 

What temp thermostat do you have in it and what brand? Like tealman said, failsafes will stick open if they get too hot.

 

I'd start with the thermostat. Cheap and easy and could very well be stuck open.