The original tank is a bottom sender/pickup tube with no fuel tray for EFI. You then have to modify it for the correct sender or make some kind of adapter for it to work with a early GM gauge, You then need a pump that has a fuel tray adapt that to the tank. If your not doing efi then a $80 tank would work but may fail inspection because you can't use a bottom pickup tank in anything that it did not originally come in. Bottom pickup or a sump pickup are not legal any longer.
We did this whole discussion 2 weeks ago about $80 tanks.
http://67-72chevytrucks.com/vboard/s...=396325&page=3