Speaking of 800 which are also rather rare .This past Saturday at a GTG I saw an 800 that was just as pristene as my 805 .
The problem with repistoning these damned things is they made 3 different bore grades of pistons .They seem to have a lot of bore grade 2 but not so many of bore grade 1 . Now you might get by with a grade 2 in a 1 bore but I've never tried it .
It was just a fact that long ago they could not hold tolerences on bore sizes but even in the automotive biz they couldn't either .I know ,I lived through it .Today they can cut stuff to a couple micron accuracy which is 1/1000 of a millimeter .That's close .