IT has to be my stock pump

The Edelbrock Performer manual instructs to regulate the feed to 5.5 psi with no more than 6 psi. Holley's can handle upwards of 7 psi. Like Cal_gecko said, even some of the stock replacements put out 7. I was looking at the specs for various Airtex mechanical pumps the other day on RockAuto and many were 7 psi - depending on model/year. 4-5 was common from factory.