Automobile Enthusiasts

Well, if the temp gauge shows it at normal operating temps then trust that. Test drive.

Maybe just hook up some other muffler, maybe a Cherry Bomb someone has or saw off something from a parts car and adapt it just to see.

It sounds like vaporization of the gas in the lines, but maybe not.

Bypassing the mechanical fuel pump by using one of those inexpensive square electric fuel pumps mounted back at the tank might help if the problem is vapor lock.

I shall now try the healing power of positive thinking until a better idea (or a smarter poster with better advice) comes along..