I have a 67 Firebird 400 that is experiencing a vapor lock problem when it gets up to normal operating temperature. I've rebuild the original Quadrajet and replaced the fuel pump. We have back blown the fuel line to check the tank filter and that appears to be fine. None of the fuel lines appear to have been kinked. When the secondaries open up the car appears to be starved for fuel, but this only happens when it is at normal operating temperature. What do I need to look for to fix this problem?  

It sounds like the exhaust passage that goes in front of the primaries is heating up the fuel too much, maybe even boiling it. Look at Mr. Gasket No. 86 or 86B. They are supposed to insulate the carb from excess heat.  

I had the same problem with a 66 Grand Prix that I am restoring at first I thought it was the carb so I rebuilt a carter and I was still having the same problem.  Replaced the fuel pump still not change.  Finally I bought an Edelbrock and re-routed the fuel lines away from the engine block.  This helped out however; I was still having issues when the secondaries kicked in.  I noticed that the fuel line was within 5 inches of the tailpipe.  What I did was purchase a few sections of 5/16 heat wrap and cover the fuel line from the tank past the exhaust.  I also placed a few pieces on the inlet and outlet from the fuel pump and near any high heat areas.  I also removed the insulation from under the hood.  This eliminated the problem completely.  Even at idle at full operating temp I have not had any more issues.  

In the high desert (3000ft, 110F) where I live, the ONLY solution to vapor lock is an electric fuel pump as a pusher.  That is standard procedure for me.

I recommend a "pulse type" that can be purchased at any auto parts store.  You can splice it into the fuel line virtually anywhere (back, side or front).  Also, you can switch it off and the mechanical pump will still draw through it.

Also, it less noisy than a "vane type" pump (Carter, Holley).  

You can fix the vapor lock problem by wrapping aluminum foil around the fuel line between the fuel pump and carb. - make it about size of a quarter - looks dumb but is cheap and works