I have run that pump on 3 different combos. All 440s, one w/ a Carter 750 carb, an 830 Holley DP, and a six pack setup. None had a regulator and had no issues w/ them. Always ran great.

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