the shelf wiseco 13.7cr (89mm) have valve relief's of .235" int & .170 exh (below Timing Edge ie TE) with the ability to increase that to .265" int & .200" exh. how much clearance is needed to run the ips cams? .290" int???
on a side note you can see some possible characteristics of custom pistons here http://www.cppistons.com/products/custom_pistons/index.html
the amount intake relief really depends on how much VTC you wanna run and of course the lift of that cam. .235 is only enough to run k2s while running 50 degrees of cam angle. With K10s you probably don't wanna run no more than 35 degrees