engine ID? question

Hydraulic motors have a different (wider) valve cover.

2806830 is the casting number for the 68-75 block with 5 freeze plugs. It's a stronger block, the earlier block has 3 freeze plugs and should have a casting number of 2463430

You will want to use the crank that matches your transmission (60-67 or 68+) in the register area. The 76+ motor will have a cast crank which won't work in the other blocks.