Hi Jason . . .

For an inline Chevy you have four choices for dual exhaust:

1) The 'old school' conversion of a stock manifold to dual via welding. Almquist used to sell the additional flange and instructions for the conversion. Manifolds that have received this treatment show up on Ebay now an again. There is one out there now.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2485161671&category=34203

2) A cast iron header like the original Fentons or Tom Langon's new design.
http://www.patricksantiquecars.com/cfentonheaders.jpg
http://www.stoveboltengineco.com/acartpro/product.asp?productid=89
There are lots of sources for Fentons including Patricks, and Obsolete Chevy. Fentons seem pricey compared to Langdon's.

3) Short tube headers - or what California Bill calls 'Clark' sytle headers. There are several sources for these -- including a place that will ceramic/powder coat their work.
http://www.hotrodsofnorco.com/header.htm

4) A modern long tube header. http://www.andale.com/stores/sf_home.jsp?mode=1&sfUrl=inlinesix

regards,
Keith

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