The standard one is .940 and the smaller one is .915, I think. Napa-Balkamp discontinued theirs years ago. Someone on Ebay sells them I believe, or take the large one and have it machined down.
Decades ago (the 70's) Dorman also made an all-brass one that fit the converter bore. Back then I did not realize what they were for. Hell I thought it was a catalog mistake.
