[JLMounce]

A -6 line in higher pressure EFI situations will support over 600 hp. -6 line should still be enough when using a carburetor for most people, but at the lower pressures you work with, the flow reduces a bit, so having that extra line will tend to help. Having the larger lines isn't going to hurt you, but you'll have to piece some things together.

You'll need 1/4 NPT to -8 fittings for the the fuel pump hat, different sized fuel filters and fittings etc. If you're doing -8 lines you really just have to purchase everything outside of kit form.