Bob .. I recall something about the 9th head bolt and can see the center hole in this block. Ah you mean those two vertical rusty posts between one and two cyl, and three and four cyl are vents which are hidden under the push rod cover ? Yes I note the boss on both sides of this block. So this is 1924 - 1926 range. Not of any historical value or use I would imagine now.
Where Are You From? Ottawa Ont
Do You own a car built by Durant? Dominion built 1932 614 Sedan
I added some more pictures to the Dropbox folder referenced above. One appears to be a date: 4 17 24. No sign of serial numbers on any of the bosses, though that appears to be a moot point. I might list it on ebay for cheap, in case someone local is interested in a relic.