To All....We used unfared heat gun...185-190 going in and coming out.
185-190 is
NOT overheating! In fact, the standard thermostat installed on these cars was rated at 195 degrees.
When you get to 220-230, then you're starting to get hot, but you're still not overheating. GM states in the Corvette owners manual that "Temperature gauge readings will vary with air temperature and operating conditions. During normal operation, gauge will indicate around the 210 degree mark. Hard driving, heavy traffic with stop and go, or prolonged idling in hot weather will produce a gauge reading around the 230 degree mark. Whenever the gauge reaches 250 degrees, stop engine and determine cause of overheating, or reduce speed permitting engine to cool".
This 250 degree limit applies to
ALL Chevrolet engines produced in the late 1960's because they run hotter than the earlier engines. This is due to an early engineering attempt to reduce hydrocarbons, oxides of nitrogen and other byproducts of internal combustion engines (pollutants), to meet EPA requirements. Before the late 1960's, distributor vacuum advance canisters were connected to full manifold vacuum. When the vacuum advance was changed to ported vacuum, this caused the engine to run hotter, thereby burning off the excess pollutants. Well, kind of! It was a band-aid fix at best and really didn't do too much in the way of reducing pollution. But it satisfied the EPA to a certain extent until better methods (like the catalytic converter) was introduced.
If you want to put the vacuum advance BACK to full manifold vacuum (and yes, this will help with overheating), follow John's instructions in
THIS THREAD. However, like I stated in my first sentence, 180-190 is
NOT overheating.
Ed
