I am currently rebuilding a 228 eng and I required a set of rings that were .020. I couldn't find any anywhere. I ended up buying a set from Grant piston rings in Calif. I am in Canada and the freight bill was high but the problem was the oil rings wouldn't fit. They sent a three piece oil ring set that fit like a glove and a one piece oil ring that was too thick. Actual thickness was 0.156 ,5/32 exactly. The rings that I took off are.154 or two thousand under and I have a partial set that say 5/32 but are actually .154 just like the old ones. I called Grant and they say my pistons are odd and they will make new ones for more money. I have checked three different 3 3/8 sets of pistons and they are all the same. Please can someone check some other oil rings so I have something to go on. Email me directly. Jim