OK interesting subject and I've been looking into it because over the years it seems my FB gets vapor lock sooner, generally what happens to me is when it was hot out, 85F and up when I stopped somewhere the fuel would boil off and I would have a hard start, generally typical Pontiac issue beause the fuel does get hotter due to the longer line going around the block and then out the fuel pump up the front of the engine, the fuel line on Pontiac V8s is exposed to more heat, add to that the stupid exhaust crossover in the intake and you're vaporizing the fuel.

Over the past several years this problem has gotten worse and I believe it's due to the increased use of Ethanol. Big oil is not always following the rules about the % but even 5-10% will make a huge difference in how much sooner at lower temps fuel will vaporize, higher altitudes with increase vapor lock too. Newer cars running electric pumps aren't as affected.

Currently I am tossing around several fixes in my mind, Carter electric fuel pump, Ram Air manifold with NO crossover but a homemade block off plate out of cast or steel, perhaps both.

Sethmast is obviously having a major problem probably from the fuel line from the pump touching the block, etc .........you're lucky you didn't have a fire, you could have a failing pump too, I have found standard mech pumps and hi perf do not last thanks to Ethanol, in fact the factory replacements from Ames last longer than the hi perf ones.