I went to a return style system a few years ago due to issues similar to your's w/ pump gas. Made a huge difference.
Back when I was playing w/ different intake manifolds and spacers, the wooden 1" carb spacer I'd been running is a big help also. Didn't realize how much until I drove around one time w/o it and heard fuel boiling out the vents when I got back home and shut the car off.
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
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