I would use -8 front to rear. It can drop to -6 after the regulator at the carb. -6 is smaller than 3/8" ID. The hose ends are even smaller than the hose depending on whose you buy.
And I would use a better pump. Those little Holleys use 3/8NPT fittings - small IDs again. Or use two of them plumbed parallel on separate switches. Ride around on one, use both when you go racing. Plus you have one to get you home when one breaks.
Using a good pump that makes some line pressure will serve to keep it from boiling or vapor locking.
