<VV> Vapor Lock

[Padgett]

>But if it is vapor lock, what can I do to avoid this, short of getting an
>electric fuel pump somewhere forward of the engine compartment?  It's not a
>tolerable condition.

Cars with a/c received a return fuel line to limit pressure build up and to 
keep the gas circulating in the system. The factory did not add cost like 
that without a reason. That said where I have seen VL in the past was from 
a fuel line too close to the block. That should not be an issue with a Corvair.

Electric pump should be an option since one mounted near the tank is 
getting cool liquid and pushing (easier than trying to pull on a gas).

That said do you have the phenolic block spacer under the carbs ? Even at 
425 the carb/line temp should not be an issue since above the shroud (does 
leaving the hood open when stopped make a difference ?)

Might want to put a fuel pressure gauge in the line (another reason to have 
a four way block) and see what is going on, could have a generally weak 
pump that is OK until experiences a hot soak.

If you want to avoid the quick fix (an electric pump) then knowing what is 
really happening is essential.

ps just as a shot in the dark, might disconnect both ends of the fuel line 
to the tank and blow it out, could be partly clogged.

Padgett