Originally Posted by CSBM5
So the car is a 2011 model then. Very strange you ended up with those bearings in a 2011.5 model (built 09/2010 and after). I have a 2011.5 built in 09/2010, and given my oil analysis from Blackstone, I'm positive I have the newer non-lead bearings.
Historically a "model year" starts in Sept after the factory holiday when all the new tooling is installed for whatever changes have been planned. As the lead exemption for bearings ended in July 2011 it would be normal for the bearing material spec change to have been made for the 2011 model year (ie sept 2010).
However there may have been engines already manufactured or lead bearing inventory that needed using up at the start of the 2011 MY run - so the actual date of the changeover remains somewhat unclear as evidenced by the oct 2010 car still having the lead bearings.
Numbers on the bearings are proof while a blackstone oil analysis is inconclusive.
You can at least be pretty certain that all cars produced after July 2011 will be with the new spec bearings.