Billet removable dome for the ADA Racing GP460 CY46 billet head kit. This dome has a .020" relief for use with the ADA Racing +1mm stroker. Use this dome with the stock base gasket and a .020" copper head gasket, no extra gaskets or spacers necessary. These domes are also recalculated for the corrected compression ratio for the increased displacement for the +1mm stroker. The compression ratio are calculated with a .030" squish clearance. Using a thinner copper head gasket and decreasing the squish clearance will increase the compression ratio. See below.