I just did this on my 1970 challenger vert, 383.
I did a lot of research.
I used the Mallory 140 with a regulator. The pump is very quiet and you should use a regulator.
If your going to go electric. it's really a good idea to have a regulator with the gauge on it. Not much more in cost and the peace of mind to know that you pressure is correct is worth it.

It was fairly easy...
I put it right in front of the fuel tank (near the differential) across that metal cross section.
I dropped it a couple inches lower by putting it on a metal bracket. You want the pump as close to the bottom of the fuel tank pickup as possible and at or below the fuel tank level. I have the pump at the bottom maybe close to the line of the tank bottom.
I drilled two holes in the metal cross section with a new drill bit and placed two straight 1" X 3" brackets (aprox) that I found (sorry to say) at home depot on the car. They are stiff metal brackets. I had to drill a better hole in the bracket but it was easy. I went to autozone and got a universal exhaust hanger and cut the rubber off the hanger. the thick rubber pad made a great isolator for the pump. I stuck that behind the brackets. I plumbed the fuel pump right to the sender by taking off the heat shield near the fuel tank to get at the fuel sender. Heat shield came off and on easy as I don't have a muffler near the tank. I used a 100 micron inline fuel filter before the fuel pump.
I bolted the regulator to the intake manifold with the bracket that came with it. I plumbed the whole thing with rubber hoses and straight and 90 degree barbed connections from summit. I used ARP thread sealant on the threads. I will switch the rubber fuel lines out someday for braided when I get the chance.


I set the pressure to 6psi. Oh, and I hear you should take the sock off the fuel sender in the tank.

Hope that helps.