id'ing different screw blowers

I have always been running roots blower so i don't too much about screws.

But i got a guy offering both a PSI and a Whipple. i don't know which specific model of either that he has. Which models am i looking for, from the different manufactures and how do i id them.

This is for a top sportsman car running a 500 tfx hemi.

Thanks

 

Get pictures, the rotors are stamped on the psi's also
just about any psi would work, the C,D, series are more prevelant. C's hard to come by as of late.
Older ones would be worth less, as would a smaller series like a 200A.may be harder to certify if that is a requirement. Theres also a gas series that may not be best for your application. recertification date also plays into value
Whipples are R980 and A980 the A makes more power and has an injector built into it.
a standard hat bolts to the R980.
Whipple has to turn less overdrive but its substantially larger and heaver than a psi

 

Thanks Shawn.

I ended up buying the whipple r980. I dont need to cert my blower as i run in an outlaw class in europe.