I've seen some nice chrome shorty headers on Ebay under Cadillac in the exhaust section. They can be had for about $125.00. Cam is a different subject. There are some Caddy speciality dealers out there that can get you what you want with just a bit of info. Potter Automotive in Chattanooga
http://www.cadillacperformanceparts.com/ Also
http://www.cad500parts.com/index.htm
and
http://www.hwforums.com/2089/ . Lux Hauler know a guy that he got some parts from that is pretty good with Caddys. Maybe he will chime in(I think his name is J Walker)
Good Luck