318 Cylinder Heads
The cracking can't be too much of an issue. My son was a tech at a Dodge dealer for a year and for the past year at a Jeep dealer. They never had an issue with cracks in the heads on the magnum engines. The biggy was leaking gaskets on the plate that covers the bottom of the beer barrel intake used on mangum 3.9/5.2/5.9 engines