Vapor Lock? 78 K20

[K20Chevrolet]

Here is yet again another post about a vapor lock haha sorry guys. Im trying to diagnose my issue which im pretty sure is a vapor lock... I have put a phenolic spacer under neath the carb ( which was recommended by my buddy who was having the same issue), Replace all of my rubber fuel lines blew out the metal lines, replaced the fuel filters. I did all of that and it was fine but noticed that i was going through gas rather quickly so I took another look under the hood and found that the mechanical pump was bad so it was spraying my fuel all over the road ( Trucks been sitting for 11 years and vapor locked before now). So during the time the mechanical pump was bad it didn't vapor lock but once I replaced it the truck began to vapor lock. When I would lock up on the side of the road id check under the hood and felt my lines to see if they were getting hot. The lines were warm but not to bad... I than check the mechanical pump and it was screaming hot so I already had a electric pump down by the gas tank to help work through the vapor lock so i just bypassed the mechanical and put a pressure regulator on the lines so i don't flood the carb. Still no luck.... So now hear I am asking for help .....The truck locks up at night and day makes no difference I have also replaced the sending unit, I Have also checked the timing its spot in.


I have a 1978 K20 Chevy
350 crate engine
Stock Quadrajet cab
Headers instead of manifolds