.005 under the deck or in the hole. The heads are some old W-2 ported open chamber heads with 70cc. no quench and low compression. I thought about milling .050 off them to make them closed chambered. but that puts the cc's about 56-58. but with a thin gasket and the piston in the hole .005 I coukd possibly deshroud the valves and get more chamber cc's. I haven set a head gasket on there yet to see how much deshrouding i can do.