toda recomends them for any mildly built motor. these are definately a street worthy cam but will require some tuning and valve train mods to go with. any b series motor with decent compression would LOVE these, but i dont think they would b enough for 12:1. if memory serves jason's compression is right around there (hence the reason he wanted to get rid of them for bigger sticks). in any event this price is great!!! ttt again