I prefer using dual feeds to the carb instead of the log/rails.. I have dual gsl 392 and have a -8 to each bowl. No issues with mile at 7psi. I also have 5/8 feeds and returns..
What regulator? Is your gauge liquid filled? What's weird with mine is when I first installed it the FP was rock steady, over time it has got progressively worse. Gotta be something simple.
I am loosing my mind. I have 1/2" feed and 1/2" return lines. All -8 accept from the sump to inlet of the pump where it is -10 or 5/8.