Sounds like some kind of erotic pleasure devece, doesn't it? Apart from the job on the head, this one needed a pedicure on the NVA and a clean-up skim on the prop driver (note the obligatory multy-grip marks on the rim). Since the driver is "splined" onto the shaft (probably with a 10 lb sledge), I just stripped it down to case + crank assy, chucked the front of the shaft and carefully skimmed the driver while the crank case flopped around on its bearing. Crude, but it came out well.