i have a 1966 396. I have gotten different answers from auto parts supply people and machine shops about what cam will work in this engine. My stock but no longer usable cam has a groved rear journal. Chevy changes this design for all 1967 and newer big blocks.

Can a '67 or newer cam be used with '67 or newer bearings installed and no other modifications?

Or do I need to do machine work to the block?

Or do I need to by a new cam and have a groove cut into it and try to find some '65-'66 bearings?