Aftermarket rockers:
Fenton claimed .065” increased lift from their intake rocker. Thomas made magnesium rockers. Gotha made rockers, but I’m not sure for which valve, the material, or the ratio.
Barker (B & B Automotive; “B & B” is cast in) offered these in 1.7:1 ratio (allow for some poetic license, it’s probably slightly less), which would have required the adjuster to be re-located toward the shaft center by .180” to 1.195”. In my opinion the claimed “7-10 hp increase” is exaggerated, and only achieved when combined with certain other modifications.
