*NOOB* about to do an LS swap

[snakedoc]

Hey guys, I am about to jump off into my first LS Swap. I have purchased an LQ4 with a stage 2 cam, 5.3 heads, and some other goodies for my 72 C10. My neighbor has agreed to help me do the swap, but I have a few questions for the general group.

1. Headers. My SBC currently has short tube headers. If I put short tube headers on the LS, will my current exhaust work? Its okay to tell me if that's a stupid question.

2. Fuel line. I'm going with the blazer tank and 97 chevy fuel pump route. The engine is a 2001, so there is a return line. Should I run -6 or -8 for the return. And does anybody have any idea how much line I'll need of each for a 72 shortbed? Is there a kit that doesn't cost a thousand bucks? I'm going to get a DELPHI HP10001 from rockauto for the sending unit/pump. I can see in the pics that it has screw on connectors. AN fitting with fit that I believe.

Thanks all, these are two questions I couldn't get solid info on through research. Any help would be appreciated.