i have a magnafuel pump 300 series i installed it in the car, dash ten from the cell ,dash ten to the regulator up front. i installed a dash eight back to the cell from the pump return. i have a mallory regulator and it can not keep up with the pump the pressure is all over the place. know my question is , is the magnafuel regulator that much better that it can regulate this pump or would i just be better off run a return style regulator. what are you guys doing any help would be appretiated i only want to do this once

A retun style system will give you a better/stable
pressure

I use a BG four port with my Magnafuel 300 pump, I had used it on the 275 pump also with no problems controlling the pressure . Are you using a fuel filter between the tank and the pump? If so do you know what size, in microns, the filter element is? I have heard of other peole having problems with the small Mallory reg on big volume high ptessure pumps. BTW, I plumb mine like yours

I had the same issue even with my Magna Fuel regulator. Call Magna Fuel and tell them to send you the spring/fitting kit that will lower the pressure. I changed this in mine and the pressure went from 26# down to 21# and now I dont have any issues with the regulator pressure....and I have the Magna 500.

I'm using the BG 4 port with my MF 500. Only return is off he pump. No problems here. At least for now anyway