Mine is 65 over which is 4.185 I think that is the same as a 455 + 30?
455 + .030 is 4.181
http://www.wallaceracing.com/cr_test2.php4.155 & 4.185 are common piston / ring oversizes, especially for stroker stuff.
https://butlerperformance.com/i-24623462-eagle-461-468ci-street-strip-balanced-rotating-assembly-stroker-kit-for-400-block-4-250str.html?ref=category:1234780;brand:99945
https://www.summitracing.com/parts/uem-ic941-030/overview/https://www.summitracing.com/parts/uem-ic941-060/overview/I figure those 2 sizes are so popular because the stock bore of so many engines is 4.125. That makes a .030 over a 4.155, & a .060 over a 4.185. So, rings & piston blanks are very common in those sizes.
