fuel pump question??

[boogieman1]

I am building a new engine for my 72 c20 and have a fuel pump question. I have a crate 350 sbc and will be putting an edelbrock cam, intake and carb on it. I have read multiple places that with that setup you need to get the fuel pressure around 6psi. The problem is all the fuel pumps at that range I can find have 2 lines, but the original is a larger pump with 3 lines on it. Can I change this to a 2 line and if so what do I need to know? Any help would be appreciated.