Ryan, unless it's a stock block which typically only handles 7-10psi with stock rings, the rings should always be aftermarket for boost. Most kits such as Wiseco, CP, Crower, Arias, etc. come with rings specifically for them. I Bought used CP pistons way back from Erik123456789, that he got from RaceEng. I am going to just buy new replacement rings for them, also probably from RaceEng. I would try calling them and inquiring, they have custom sized rings for race specs. What pistons are you planning on using?