I have a 1980 Z28 with an original 305. I live in California, so my options are limited. I would like to replace the stock exhaust manifolds with either a higher flowing cast iron chevy exhaust manifolds or with headers that have the air tubes for emissions. Does anyone know if some the the third gen headers fit and clear on the second gen's ???

Hedman 68601 has the air tubes and will fit a second gen. They are not full length headers and are considered medium length. Here is a picture of mine on my '77:

http://community.webshots.com/photo/71819704/352265633LDPXfW

Hedman has both full length and shorty Carb legal headers, but I think they dont fit with a z/28 close ratio steering box. Maybe the exhaust manifolds by Sanderson Headers on another thread may be your best bet.