1967 318 Barracuda running hot...

Badfish1 said

I now have a 160 in. It doesn’t leak fluid and the heater works. I can hear like thumping or bubbling in the dash it seems on the passenger side and the fluid boils after driving...really want to drive car to shows and stuff...could the timing have anything to do with it? Thanks
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The Thumping is the coolant boiling, are you using antifreeze not just plain water? Like Dana67Dart said go back to the stock thermostat temp 195+/- you could be getting hot spots from unrestricted flow creating hot pockets in the circulation loop. Plus open the heater so that whats in there will circulate in the event you are getting air pockets.