When I look at a GZ motorsports vacuum pump, it looks like and OEM GM smog pump from the early 70's, except with a different inlet or outlet drilled and tapped into the case.

The GZ is $500, the smog pump is $89 at Rock Auto.

What is the difference, can a smog pump be used as a vacuum pump on a race car?

Thanks, Joel

Thanks, Fred. I am not refering to an electic pump though, I mean the old belt driven smog pump. The GZ motorsports pump looks like it is based on the GM belt driven smog pump.

This explains rebuilt for the oil??
http://www.dragstuff.com/techarticles/vacuum-pumps.html

here is the oem pump:

Here is the GZ pump: