Was given a water cooled head for a OS motor many years ago . Not marked as to which but its either a 10 or 20 . Memory fails but think the donor said it was for a 10. Anybody interested please PM me - don't want anything for it other than the postage obviously...... can probably get it to UK for free + UK postage from Hants - might take a while. Oz & NZ only by post..........