Help with Sandborn Magna Force compressor

[planecrazy29]

I just bought a 5 HP, 2 stage compressor from Craigslist. It's in decent shape, altho the tank may be shot. I'm working on that. My question is about the pump. The seller told me that he just replaced the head gasket. The pump now makes a chriping sound that starts at about 50 psi. It seems to pump pretty slowly, but makes it to 160 PSI with no problems. I got a good enough deal on it that if the tank is shot and the pump is repairable I'm still ahead.

The seller made his own gasket out of auto header gasket material so my first thought is to buy the correct gasket. Thoughts?

-Aaron