20-10-2020, 08:11 AM
"Wedging" the earlier low compression head by surface grinding is/was a way of increasing the compression ratio without resorting to the late 37 head or similar such as Alta , Ricardo and others. The holes for the head studs require easing to allow for the angle. In some respects the wedging of an earlier head is better than the late 37 design as the plug location remains central to the bore. Metal is removed from the side of the head furthest away from the valves until close to the plug hole, maintaining a flat surface across the head. Hope that makes sense.