That discussion was around the 724 intake which is the B version of the 725 intake that I'm running on this motor. Those are the M1 intakes with standard runners and 4500 flange.

There is also a RB intake with Max Wedge runners that Mopar used to make that they might bring back. I think it was just a 4150 flange though. Kind of funny, MP had these intakes around before there was much demand for them so they killed them off. Now there are a bunch of motors being built that can use the big carbs and big runners so the intakes are coming back.

Still no one makes a RB (or B) dual plane with 4500 flange. I'd run one on this motor if it was available.