I think you're confusing delta with AMC. AMC is the vendor for aftermarket heads... delta makes a reground camshaft to go in them.

In addition to the AMC casting, there are also two distinctly different OEM castings of the factory heads. The earlier castings are the ones more associated with cracking. I don't think the problem is nearly as prevalent with the later year castings. I doubt what you're referencing to is identical to the AMC casting.


-Rob