If you are looking for NOS piston rings for our Continental engines, give Otto a call....Most ring suppliers don't carry the 3/16" wide rings...I had no problem getting a set of rings for my W-6 Continental with an .040 oversize, his prices are reasonable and were shipped fast....You may need to let his phone ring for a while.
Otto Gas Engine Works
2167 Blue Ball Road
Elkton MD 21921-3330 USA
phone 410-398-7340
http://www.ringspacers.com
http://www.pistonrings.net