In case anyone gives a rats ass.. My 312 fastech with 454mag mpi's was vaporlocking. Merc puts the fuel filter right on the motor then runs the fuel lines on the hot motor to the VST but says they like the fuel to stay below 106deg F while your motor runs at 160-170degF...DUHHHH SHut motor off and poof. Heats that fuel right up...Freaking engineers..
So I moved the fuel filter to the back of the seat on he bulkhead and jerked the fuel lines out held nice and tight to the motor.. Installed new braided fuel lines away and off the motor and on the top and side of the plenum, Looks nice costs
about $130.00 each motor and 3hrs each and I'll be damn it works. Ran the crap out of her to get hot. Shut her down and let it sit for 15min's onetime and 1/2 hr another and an hr. Fired up and gave her the gas and we were off to the races.
May not work for everyone but sure beats doing all the other stuff with extra fuel pumps etc.