only know a couple of stuffs, those gadgetman groove, and singh groove.
don't know the truth about either, but both are very promising. from my initial research about singh groove, either they try them and happy with them, or say it didn't work, but never try them. have seen a couple of dyno sheets, and a couple of gas analysis data, which shows improvements after modding their chamber with singh's groove. my proposal is, if anybody want to know the truth, get a fresh bottom a12, and do those singh line on a roundport head, and see what happens. use regular gas. everybody here on this forum kinda know how stocker a12 goes, right? see if there's any improvement using buttdyno :)
http://www.somender-singh.com/http://www.herningg.com/singh/http://www.jeremiahsviolins.com/grooves.htmhttp://www.mgccars.com/groove_101.htmkeen to try those singh groove on my A12A, but currently not enough money to do so, as all my money goes to my 510 :)