Have Stepped Headers Been Proven Out ?

[Alan Roehrich]

Header design, including single or double step headers, or 4-2-1 (Tri-Y) headers, as well as merge collectors, requires development of a package.

You cannot simply bolt them on and expect improvements, it just does not work that way. Making them work requires changes to the camshaft, as well as the fuel and ignition tune, in order to see positive results.