[Dark_5.0]

I cant be sure with out being there but with what you have listed I would be very surprised to see you make much over 300 HP.

48 psi is way too much fuel pressure. 48psi with 30# injectors is enough fuel to support 470 HP.

You need a bigger pump for sure. And IMO even then your ideal pressure will be a little over 20psi which will give you a poor spray pattern.

You can get by with the 30 # injectors until you upgrade the engine but you will be stuck with a poor spray pattern because of the low pressure.