there's no coating for pistons other than hard anodize that can make up that size difference. those pistons are made with at least .0045 clearance in them so they would measure 4.0655, that leaves you .0115 piston to wall minus .001-.002 spray on moly coating. the moly coating is sacrificial and won't stay there for very long. i think that's way too much clearance. it may be time to just hone it to 4.08 and put the right size pistons in it, if the block will go that far. most factory blocks will be paper thin at that bore size.
Like I said I can go with another block which is 4.070
and have the coating removed but it will need to be
decked to my set up(rod, piston, stroke combo)
