If I'm not mistaken, the int. valve is around 2.15 min std with those 9's and can go to 2.18ish?. With that size plate the cylinder is the restricting factor on these sm. blk strokers. This is not me. This comes from guys that build these heads and engines often. I've got a set of Indy's that sport 2.15" int. and was cautioned by the porter that these heads want lots of piston. A min of 4.07" was min. and that was the beginning. A 4.10" was better and still not the optimum size. I believe most of these flow numbers in these heads are given with a 4.25" fixture.