Just treat it exactly like you would an LA small block. Use the same selections.
A cast iron cam, or one with a cast iron gear specifically called out, can use any standard gear intermediate shaft. I use the Mopar Performance version just because they were easy to get.
A cast steel camshaft or billet camshaft should use the bronze gear or the Crane treated gear.
Basically the same info you already know. Don't let the Magnum version of the engine change your opinion on this. No good gears specific to a Magnum are currently available, but LA versions are the same within these guidelines.
I am using mostly Howards and Hughes engines camshaft because they specify clearly that I can use the standard gear. Supposedly Comp camshafts can be ordered specifically with a cast core but their quality and support turned me off of them so I won't try those.
