5/16 in line fuel check valve

Best thing I ever did (before I went with EFI) was 1....rear mount electric pump, which helps prevent fuel boil/ vapor lock, 2....A nice fat insulator under the carb base, and 3....A vapor return system utilizing the popular Wix filter with built in orifice

First time I ever saw a return system.....and they WORKED was on my 70 440-6 RR