I found out about them on FB. Here is the full info on these heads:
The LS community has been waiting for someone to come out with an LS3 style head that can flow serious air on the exhaust while keeping the intake port and valve small (well, smaller than stock anyways).
We are proud to announce the release of the SPS Haymakers! What's better than a stock size port with a smaller CSA, smaller valve, and still sees more air than a ported LS3? (This head was not based around flow numbers btw)
.750 deck, 4 and 6 bolt castings available
2.125/1.600 (2.165 and 2.200 valve options available)
11* valve angle
Chambers start at 74cc but can milled down to desired volume
Custom stainless valves
Bronze guides (powdered metal guides are available)
Custom billet rocker pedestals
Last edited by KCS; 03-09-2017 at 10:58 AM.