well I`ve been using an elec GM air pump (vac pump) with a voltage reducer to keep it running cooler,,pulls lots of vacuum, and I run the system open with a lite restriction on the intake end,,pulls way more than the header style evac,,,maybe 10 times more,,and you can mount the pump were ever you want,,only draw back is you need a good separator tank,,I use it mostly just for the track,,,and it works great,,,,pulls as much vac as my bros aerospace one,,and at least 1/2 the cost