I picked up a used VS57 unit yesterday for my 331 stroker build and I'm still a bit confused on the fuel pump issue. In looking at some schematics in PDF fles for the original VS57 set-ups, it shows an electrical and mechanical fuel pump. In talking to others, I'm told that all you need to use is a mechanical fuel pump with a drilled and tapped hole in the top of the pump (in the correct location) to run a vacuum line from the pump to the S/C unit. Can someone explain the method they use for providing more fuel at higher RPM's and less fuel at lower RPM's?

Thanks,

Rono.

  Ron Lane,  Meridian, ID