Oh, thanks Tim. I think there was a lag on the forum cause I just scrolled up and saw your post.
ON that serial number, the digit after the 2 is definitely an "I" and not a "1". Not sure if that changes anything.
Head casting code is 3836848
Block casting code is 3769716
I haven't started to take anything apart just yet. I want to make sure that I have the right manual before I take out a wrench.