when you add the Aeromotive fuel pump and by-pass regulator to the 454mag mpi. What do you do with the little stock regulator that has the vacuume line running to it on the fuel rails crossover on the front of the motor.
I'm ****-canning the mechanical fuel pump and the VST.

Doent that vacum line change the dynamics of the regulator, as in keeps pressure constant with increased flow rate. How does the Aeromotive pump compensate for this.

Like you I do not care for the stock merc cool fuel unit mounted to the underside of my block, totally different than the vst unit.

I assume you will adding an aeromotive regulator along with the fuel pump. If the stock regulator isn't needed you can just leave it and get a brass plug from procharger to plug off the return line on the back of the fuel rail.

The regulator on MPI actully goes on the return side of the rail.. and has the regulator has a return port to send fuel back to the tank.. I just don't know if I plug or leave the little stock regulator alone.. Its the one with a vac hose to it.

Does anyone know if I should leave the little stock regulator hooked up when I add the new Aeromotive pump and its regulator??

You don't want it hooked up, and only need/want 1 regulator. You can disconnect and plug the return port off it. If you want to remove the regulator for good you will have the make some kind of blockoff for the rail where the stock regulator mounts.

Did you ever find a blockoff? I am having the same issue!

mine on my 500 efi is a symple tap and thread in a plug to the rail