I bought a used GZ vacuum pump from Rich at Fastman EFI several years ago, I called GZ and ask about where to put the bypass valve and where to put the input line to the pump. They said to put the bypass valve right beside the pickup line so I wouldn't be sucking dirty air from the outside across the motor once the bypass valve opens
I ended up putting both fittings on the passenger side front valve cover as close as possible to the pump
I did have a thin aluminum home made baffle welded under both fittings, I drilled a bunch of 1/2 inch holes in it, it runs half way down the valve cover to try and keep the pump from sucking oil into it. That seems to be working good, I get a lot, less than a lot really
, maybe a ounce, of condensation out of the sump bottle when I drain it three or four times a year.
I haven't put a filler cap into it yet either
I will, soon
Luckily this motor doesn't leak oil anymore or use oil, the oil stays a lot cleaner now longer also
On the filler cap I would put it on a flat surface as high as possible on the valve cover closest to the intake manifold to help the oil drain back into the motor from the top side of the heads instead of from down low, especially on a hemi motor, so you don't flood the lower drain back holes in the heads