val and val. job??? for the head guys

he says the val. are the ones that came in the heads and hes looking at the milidon,or the farr(i think) thats nail head....i have milidon in my heads look like a good val. not very high dollar wise.....what amount of power could this result in would it be noticed .....what would you guys rec. as far as val. and the 5 or 7 ....