Thank you for answer! My machinist check the decks for straightnes and say im not need to mill but he not check any deck height. I meassure all 8 pistons in different area using a steel ruler and a caliper and find them all be around 0.040" under so i know the deckheight is about .018" taller all over than it theoretical should be, i just wonder and thats why i ask if it is common and i have understand that its common the blocks are not straight all over but this one are straight, just slightly taller and in my case thats just good i belive because it keeps the compression down a bit.