My 1972 350 4bbl starts first time when its cold from the night before, and drives good. But when I park it for maybe twenty minutes and then go back out to start it, it takes around three tries, and me pumping the gas pedal. What could this be? Why is the heat making it more difficult to start?

Probably a heat soaked starter motor.

Two things happen when you bake an electric permanent magnet DC motor beneath the heat of roasting header tubes. First the magnetic power of the magnets are reduced by heating (which is why super cooling them makes them work well enough to pick up a train). Second, everything expands which reduces all of the production tolerances to the point were they start to bind. You need to place a sheet metal shield (multiple layers work best) between the headers and the motor. Placed such that the electrical wiring does not saw off it's electrical insulation getting past it.

Big Dave

I saw an article in one of my magazines recently that mentioned heat transfer to the carb causing starting problems and I think it was Edelbrock who makes a special gasket that doesn't raise your carb, but it does insulate it from the heat transfer from the intake manifold.

As far as that goes fuel can boil out of the line from the fuel pump to the carb if it comes in contact with the block (transfering heat).

To really figure out what he means by hard starting we need to know if when he tries to crank it over 3 times does the starter not want to spin the engine or does it not want to fire? Depending on which one it is it would let us know if we have a starter issue or fuel/air/spark issue.

To really figure out what he means by hard starting we need to know if when he tries to crank it over 3 times does the starter not want to spin the engine or does it not want to fire? Depending on which one it is it would let us know if we have a starter issue or fuel/air/spark issue.


The engine is being turned but does not catch. Also if it helps this is a recent problem.

To me it sounds like a fuel issue. Are all your fuel lines new or old? (an old one could have a pin hole in it that either a lets the gas leak out of the line from the tank to carb or lets air into the line and allows the gas to flow back into the tank, New ones could have a connection that isn't totally sealing) Your fuel pump could also be allowing the gas to flow back through it when the engine isn't running if it is bad. Also check all your fuel lines and see if any are resting on the block or close to the exhaust pipes. Fuel exposed to the heat to long could be turning into a gas form. Last but not least check to see how hot your carb is after you have driven the car. If it is to hot it could be evaportating the fuel in the fuel bowls and such.