Of course it's the rings...even the guy who put them in my 340 said he has used lots of sets of them ...but always in 1/4 mile race engines where they might see 20 miles in a season. Mine was the first set that he put in a street car, and he won't be using them again in anything that will see street use...he spent Drag Week with me pouring oil into the engine so he learned his lesson!