The Jalpa uses a Sanden 508 compressor. Very common. I know the street rod folks use them all the time. Here is a place where you can get about 10 different varieties (polished and painted to just normal cast finish):

http://www.streetrodstuff.com/Products/1345/

I believe that Chad sells them also.

__________________
Mike
Jalpa #12071

Aerodynamics are for people who can't build engines -- Enzo Ferrari