[356RS]

Chris, I measured a 930/25 case ( 1987 3.2 ) and found the head stud case hole to be 34.75mm to 35.00mm total depth. The bottom of the hole has an un-threaded area of 6.5mm in depth. The studs are 163.75 to 164.00mm in length and the case end threaded portion is 25mm in length.