"IF" I were to convert to the electric pumps, I was planning on finding the fuel pump trigger wire from each ECM and use that wire to trigger each relay for the fuel pumps. This way, the system will prime for 3 seconds when you first turn the ignition key as programmed for the existing EFI fuel pump.

This Weldon pump seems to be designed to pull fuel and can be mounted as needed without the worry of cavitation.

http://www.weldonracing.com/product....)_Flow_Through

Here is a picture of the way I installed the Holley marine pumps as a secondary. I added mine at the water seperator.

Have you had any cavitation or thermal shut off problems? How long have you been running this setup?

Zero problems to date. I've been running this for more than 2 years. Very pleased with it, I did not have the mechanical fuel pump on mine. I was having problems with vapor lock issues before I added the 2nd fuel pump. Ever since I've added the 2nd pump I have not had any problems.

I went with Mallory pumps. Installed them mid August and already had my first failure after 2 runs.

That is the pump I run, 4 years now with no problems. On a 540, n/a, 625 hp engine.