Been having problems with my 68 454HO running out of gas on heavy acceleration & going up step hills. It has a mechanical fuel pump. So I decided to install a MSD red elect pump. Mounted up behind the license plat & fabed a stainless steel box to hold it. Ran the wires over the rt frame to the rear box to a circuit breaker & relay.  Just using the circuit breaker now. Made a big difference but stupid me thought the problem was still there  until I realized I have the MSD distributor set for 5K so I don't over rev.  It revs so fast in 1st,2nd & 3rd  gear I can hardly shift fast enough. So I'll set my tach light at 4500rpm.
Almost forgot when I first hooked everything up the fuel went thru the mech pump too...it blew the diaphragm in about 20 seconds & started leaking gas,  so it's out of the loop now. I do use braded fuel lines up frt & a filter before & after the fuel pump. Can't hear the pump with the engine running :D
Alan [smiley=beer.gif]