re: Blue smoke -sequel

>>rebore, new pistons and rings 3000 miles ago.

  Were they "County" brand pistons/rings?
  Friend of mine had a problem with those recently on an MGB engine.
He ended up putting new pistons and rings in -again-; different brand.
  Probably fewer miles than yours, but when he removed the old(new)
pistons he said he could easily squeeze the rings into their grooves
with one hand.
   Ed in NC