I am running 24lb injectors with the stock pump. What i am needing to know is the max fuel pressure you can get with an adjustable regulator and a stock pump? Can't afford the upgrades right now but don't wanna starve my fresh 385!

 

What kind of flywheel HP is the 385 making? Your injector size should be about 0.07 X the flywheel HP (rough guideline), or about 35#/HR on a 500HP engine. To make a stock 24# injector (24.9 #/HR constant) flow that much, you would need to bump the fuel pressure up to 86psi. The stock pump isn't going to supply adequate flow at that pressure, even if it could reach it. As the system pressure goes up, the pump's flow capacity goes down. And the stock RP injectors (if that's what you have) will not function at that kind of pressure. A pintle style injector like the SVO's, FMS, Bosch, etc. will, but not the ball & seat stockers. They'll lock up at that pressure.

Given the relatively low cost of a set of ~35 #/HR injectors, screwing around with excessively high fuel pressure would seem like a recipe for disaster.

 

a walbro pump is cheaper than a regulator (if you don't have that yet).