I just got my brand new inline fuel pump tonight. I read the paperwork and they say the pump requires minumum 1/2" fuel line supply and return. It's the Mallory Comp Series 110FI (EFI 60psi pump).
I know the stock supply line is 3/8" and return is 5/16".

Do I need to change these to 1/2" all the way to prevent early pump failure?

The problem is going to be pressure drop (too much flow for the small ID lines). This site speaks to design criteria for line diameter, and how it will affect the FPR:

http://www.gnttype.org/techarea/fuel...nearticle.html