So I think I've replied to a similar topic in the past, but will summarize my experience here.
First I have a late manufacture 260Z so it was already equipped with an electric pump as well as mechanical. It also had the original convoluted wiring scheme that only turned the pump on under certain conditions. One of my goals of this mod was to be able to "prime" my Webers with the key in the on position. I find that when the car sits for a while the Webers will get dry and the mechanical pump by itself was not sufficient to provide that prime.
I did eliminate the mechanical pump entirely. I wanted to be able to use the existing mounting at the back of the car near the tank for the new pump, and managed to find a brand new pump that was a carbon copy of the original one that came with the car. The pump is a Facet / Purolator FEP-60SV and bolts right up to the OEM mounting points. The pump does give off some noise / ticking which is noticeable when I'm priming the carbs and the car is not running. I actually like this as I know for sure that the pump is running, but one my car is started, you don't hear it at all, especially over the exhaust.
I completely removed all of the OEM hard lines as well as the return. I run a SS braided line directly from the pump up to the passenger side part of the firewall where it terminates into a FPR I believe made by Summit Racing. From there I run a line from the side output of the FPR around the valve cover where it terminates into a 3 output fuel log which feed each of the 3 Webers. It works great without a return and I've never had vapor lock problems.
Hope that helps.
Mike.