Which year or years 360 is best

I've seen mold changes over the years but I've found the later ones to be cast more accurately with less iron, but not always with the desired result. I've also heard (again, I think more of a rumor) that the factory in the mid 70s lowered the quality of iron but added thickness to the bore cores so the strength was not affected. I think unless you were worked at the foundry, you won't "know" for sure on much of anything other than they are iron...lol.