1969_Mach1 333 Report post Posted May 19, 2021 I'm looking at mechanical fuel pumps for a 390 in another project of mine. The specs for stock pumps give a minimum flow rate of 25 GPH at 500 engine RPM. Aftermarket performance pumps like Edelbrock or Holley only give a maximum flow rate spec. Before spending $160 and up for an aftermarket pump I have some questions. 1) Motor is mild and will make roughly 400 hp. I know 25 GPH is too low for that, but that is an idle spec for the stock pump. Will the stock pump flow much more at higher engine RPM? 2) Is there a stock pump that flows more than 25 gph? If so what is the application? Thanks Quote Share this post Link to post Share on other sites