You can plug them all. the one under the distributor is used most commonly because it near the harness. there's one above the oil filter outlet on the left side you can use. its the easiest to get access to in most cases.
the switch in your link is for the old style single wire gauge. its not anything more. the newer ones have the 3 wire center for the TBI and fuel shut off. if you plan on running a manual gauge then just add enough brass from the top one to get the line out where you can reach it.
Last edited by Yetti; July 5th, 2011 at 09:49 AM.