Thanks Jerry. I never knew they were slightly off-center but that does make sense. I have a brand new set of hydraulic lifters (bought circa 1980) for the 235 and they are convex by about 8 thousands. I've kept them along with a brand new cam bought at the same time and will use them someday. Also when I rebuilt the 235 I'm using now I used the cam and lifters from another 235 I had rebuilt in 1977 because they still seemed fine and those were only slightly less convex than the brand new ones (may have had 10,000 miles total on them). The lifters I'm using now were sold under the Sealed Power name and the new ones and cam were more expensive.
I have no idea if anyone in the world is still doing this (and I'm certain Jerry can give some thoughts), but when I was in high school, the parts house in our village could send lifters off to the machine shop in El Paso who did all their work and that shop would re-crown them as long as they had just worn to the point of being flat. The man who owned the parts house said he had seen the machine they used and that it was fascinating. I never had this done, but friends of mine did and said the lifter bottoms came back like new. It was about $1 less than buying a new lifter. One of the mechanics in town told me he did it any time he had to do a valve job and said he considered it an insurance policy. This was many moons ago...
