FWIW, I have been running 35 lb/hr 2.8 injectors at 45 PSI lately on an essentially stock 350 TBI (TPI pump/Experimented with the regulator spring with ones I had laying around). That is about 68 lb/hr from 35 lb/hr injectors or roughly 2x stock. I am having no problems with a NEW stock type diaghram or the injector o-rings at this pressure. The injectors are a little noisy, but current draw really hasn't changed much if at all. The injector spray is barely visable and I have hit 20 MPG highway in a 1991 G20 Van 350/700r4/3.42:1 combo. Very smooth idle, seamless throttle response, and good torque.

20 MPG ???? Holy

I should have no problem feeding a 330 horse small block with 68's at a higher psi, then. Where is that formula to find out howmuch psi to run?

I would be interested in the limits of the stock fpr if anyone could add that.

I want to run a walboro pump that puts out 40-50 psi. Will I run into problems reducing the pressure below a certain amount?

I don't mean to jack the thread, but I feel this may be relevent to the topic as well.

I'm running a Walbro 307M on a 4.3L V6 with no problems, I made my FPR adjustable but hadn't touched it after the FP install. runs fine, I may try leaning out the fuel curve some but that's unrelated.