Engine Block Crack?

[Neuner]

Pulled the AMC 258 i6 / 4.2l and noticed an unusual jagged line/residue on the block below the manifolds. Was getting late and wanted to post the attached photo before I cleaned it up in case I loose track of it. Does it look like a crack?

Not sure if you can see it in the pic but it has a thin raised residue of oil like a mini mountain range that follows along the jagged line which is what caught my eye.

 

[Lumpy Grits]

Take a steel brush to the area and clean it up.
Don't think it's a crack-
LG

 

[jammer1]

I agree, take a can of carb cleaner and clean it. Then take the metal brush to try to get rid of any scalling. May be the plug leaking and following a casting flaw.

 

[Torxhead]

Looks more like a leak from that upper plug to me.

 

[Hedgehog]

Slow little dribbly leak.