The number one improvement I can say should be done to small blocks are the oil holes behind the filter in the adapter plate.

340/360 LA & 5.9 Magnums are supposed to have 6 to 8 holes for oil to pass from the block to the filter. 318 LA & 5.2 Magnums usually have 4 holes and that is too few.

First thing I do is add more holes or replace the 4 hole plate with a 6/8 hole plate.

Oil is your life blood for an engine and mopar gave the 318's a clogged artery.

I know you said yours was a 5.9 but look at that filter plate. More holes won't hurt a bit.