Im having trouble figuring out the date codes on a block i have. Its a 3970010 4 bolt main block, I cant find any date codes on the flywheel flange, the only #s i see that can be dates are on the right side(In the middle, between the frost plugs) they are 1 K 26. I always thought the last # is the year, but a 26? Any help would be appreciated.

K denotes November. I would guess 1 K 26 is November 26, 1971.

Thanks, that explains the other block i have too, its # is 1 L 8. December 8, 1971