FYI - Been busy measuring and fitting rod bearings the past few days.
On Sunday I attended the Maple Grove Raceway Swap Meet. Stroke of luck, a vendor was selling a bunch of different BBC Clevite Rod Bearings. Some were full sets, some with a few missing. Some STD, .001, .010 and a few others. In there were:
(17) CB743HN Upper STD (all date codes 21)
(11) CB743HN Lower .001 (date codes 20 & 21)
So not very old. Got the lot for $100, a total of 53 total shells. Some had bore gauge witness marks. All got me in the .0024 - .0027 range. A lucky day for sure.