Ok I know this had to be covered 800 times by now but I have spent almost an hour searching and cannot locate a specific answer. 88 350 TPI my fuel pressure is at 37 idling, when I open the throttle I will get spikes up to 42-44 or and if I hold it at about 1/2-3/4 throttle I will get about 40. Is this about right?

If I go to a AFPR what should I set the idle pressure at?

 

That's within reason.

To adjust an adjustable one, you first disconnect the vacuum line to it while the engine is running; that will make it go to its highest value. Then adjust it by whatever measurement means you see fit. You could use best ET and/or MPH, highest HP reading on the dyno, O2 Sensor reading just below 900 mV on the dyno, etc.

43 psi is about the factory spec so yours is doing about what it's supposed to.

Every engine is different; but if you've done anything to increase the engine's airflow, chances are, a slightly higher pressure will give more power. You can't really go past about 50 psi though, as the injectors start having trouble working right at much more than that. If the engine wants that much more fuel, it's best to go to larger injectors.

Most people seem to get best results on a typical TPI with typical mods (light porting, headers, etc.) at a setting of about 45-46 psi.