There are no cast roller cores for BB Mopars.

Copper color between the lobes is 8620 material.
Black between the lobes is usually 5150 material.

The heat treat goes deeper on the 5150, which allows for more manipulation for putting a wider variety of lifts and LSA’s on the core.

Both are steel billet.

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads