Couple install price ?'s
Headers
Cam & Springs etc
Heads
Intake manifold
Anythign else thats common?
Thanks
http://www.go-fast.org/z28/headers.html
http://www.97ta.com/flp_header.shtml
http://www.fbody.com/tech/details.cgi?id=65
some of them include more install guides than just headers.
as for prices expect about $400ish for installation of headers, dunno about the rest but I would imagine $1000plus for cam etc.

