tufcj
The last digit or 2 digits of the year are SOMETIMES cast into the lifter galley of the block, or into the heads in the same place as the casting number but on the opposite end. If you have the crank, a date is sometimes stamped into the front most counterweight.
It doesn't really matter, they're all about the same. Some of the very early 360s had a little thicker main webs (up to 74 I think). The later ones (late 80s, 86? up) had 2 extra freeze plugs in the back, under the flywheel. Journal diameters, deck height, heads, rods, pistons are all the same.
Bob
tufcj