BMW M50 S50 S52 Drill Jig M11x1.25mm Cylinder Head Stud Conversion
$300
Modify your M50/S50/S52 block to accept ARP S54 (M11x1.25mm) cylinder head studs. This leaves a small amount of the original threads in the block. The trick is to engage the M11x1.25mm tap into the remaining threads and 'chase' them.
