Hello Inliners, a new Inliner here.
I've recently acquired a complete 261 out of a Canadian 1961 GCM school bus. The engine has been completely dis-assembled and is ready to go to the rebuilder to be cleaned and verified.
Here is what’s puzzling me, the casting # on the block is 3769925, and from what I've seen listed here on Inliners (and elsewhere), that translates to a 1958 to 1962 261 block.
The date code cast on the block is "C 1 6", this suggests the block was cast either March 1st 1956 or March 1st 1966. How could that be if the block is supposed to be a 58 - 62 casting? The other odd thing with this block is that there is no engine id number stamped on the machined pad beside the distributor.
Any insight from the Inliners is appreciated.

Thanks,
Alan