[Mike Semeniuk]

The 010 / 020 behind the timing cover blocks were the high nickel. Quite a few of them were in the 350 powered trucks - in Canada at least. The later versions had the oil galley tapped above the timing cover. Prior to these, the 509 blocks were the best and I believe from late 60's 327 and 350s. they were meater. kind of like the mid 60's 283 blocks with the deep oil filter pad. We used to have a wrecking yard and saw all versions of these over the years - but not as many as some would think. - or hope.

There are letters stamped on the oil pan rails by each cylinder that supposedly indicate how concentric the hole is. The 010/020 blocks had the least deviation of letters between the 8 cylinders - but then again, that may be an old wives tale.