Slant 6 block casting numbers
That appears to be all the numbers.
F 530-6 3338
KHK
It does have the 5 freeze plugs on the left though.
The following is on the R/H, front side, stamped next to the deck next to the cylinder head: 9225R 2 15 CE
Further checking shows a cast crank and cylinder head 81-87 at
http://www.mopar1.us/casting.html.
Perhaps the block is of the same years....???... It does appear to have solid lifters though, weird.