Fuel Pump Mounting

1/2" at least.. put a crayon mark on the pipe closest to the fuel line, if it dosn't melt after 10mins @ 1000rpm or so, your safe.
AS far as mounting the fuel pump, best bet scenario would be to put a fuel cell in the trunk, and mount the pump(s) to the frame.
use rubber isolators. let gravity be your friend.

FASTBACK340,
sweet setup man! u gots the skills to pay the bills...