Heating up on highway ?? 72 SSP 440

[jprather]

Demon 850

 

[brian6pac]

Pinging is caused by high combustion chamber temperature, more fuel will cool it down. My friends car had a vacuum leak at the intake to head gasket, it had a edelbrock intake and who ever put it together only used the valley pan to seal. It did the same thing got hot at high speed around town it was fine. Take a long piece of vacuum hose stick one end in your ear and go around the intake and carb and if you have a vacuum leak you will hear it. his was leaking bad from underneath get the hose under the manifold as close to the gasket as possible his was real loud. We put a paper gasket and a new valley pan on and what a difference.

 

[moes]

How do you know it's rich cruising at speed, I bet it's lean. What carb is on it?

this is were a AFR gauge would help, I installed the same one on my cars over the years. I just remove it (put in a plug in the exhaust were the O2 sensor was) before I sold the cars.