77 302 Ford overheaating. Replaced thermostat....new higher pressure radiator cap..,Flushed out radiator, flushed out engine block....swapped old water pump with new High Performance Edebrock.. still overheats...top and bottom hoses pressurize hard as rocsk but bottom hose remains cool? overflow tank perculates... any ideas on what I'm missing.........

 

I worked on a 76 1 ton with the same problem turned out to be the wire was making contact with the block it would not happen all the time. Also make sure the rad cap is okay.

 

Sounds like it may be a bad head gasket.[hr]Exaust getting into the coolant.

 

If there's moisture in the spark plugs, it could be a blown head gasket that's causing it. Check also for possible leaking intake manifold and anti-freeze.

 

save yourself some time and get peace of mind. Go to NAPA and get head gasket tester. It test for exhaust gas in the coolant and that sounds like it might be your problem.