1988 foxbody with 5.3 swap
Walbro 255 in tank pump using stock mustang fuel lines
And corvette filter/regulator. Stock LS1 injectors

I have a nos sniper kit with fuel and nitrous silonoids,
I'm trying to figure out which size jets to run to make a 100 hp shot but I'm unsure of fuel pressure. How do I determine what size jets to run and my fuel pressure?

 

Put a gauge on it and measure would be the best.

 

corvette regulator should put you at 55~58 psi.