Mazda Miata 1.8 lts 83.50mm(+0.5)/ 4032/ Forged piston/Comp. height 30.5mm (STD)/ 10.5cc Dome /20mm pin Off Center/ Rings 1, 1.2, 2.8mm. /Valve pocket depth Int.: 4mm (diam 36.5mm) Exh: 3mm (diam 31mm) /C.R.: 11:1