Vapor lock issue?

Ok so Ive insulated the lines. Gonna see what happens. Buddy of mine has a 68 340 Formula S that does the same thing even worse so I've insulated those too. His is the only car that has been tested with the insulation and so far it's helped some but fuel is still vaporizing in the lines up to the carb and causing sputtering. No where near as bad mind you. Any more ideas. I've heard the fuel pump getting hot can cause it too.