hi john,std deck height on cosssy yb is+ 0.45-0.5mm,any more may cause pistons to clip head under full load as rods stretch and as bearing and pin clearances add up.WRC gasket is normally 1.15mm compressed so you should run at least 30 thou or 0.75mm clearance between piston crowns ane head face.1.15mm(check each gasket though)-0.75mm=0.4mm max safe deck height-regards PJ