[storm9c1]

The stock Dormans I've seen (the truck versions with the angle dumps) need no casting grinding. They seem to fit fine. They do NOT have any alternator or A/C extensions nor do they have the weird "choke pipe" that the Vette ones have.

The 2.5" center dumps are for the Vette and are different. They can have various different extensions and the chock pipe.

Also, if any ram horns are used on a center-bolt (newer) head, then there is a chance that one side (I think driver's side) has a cast that hits the overhang of the valve cover. In this case, it will need some grinding. At which point, you might as well grind off all of the ugly castings and make them look really smooth while you have the grinder out.