You can email Brady Basner at Powermaster. He helped me with two dual field alternators.
bbasner@powermasterperformance.com

Did you try a 72-74 Roadrunner when talking to the parts houses? The later year car may show a dual field part number.


1970 YO7 A66 [Canadian Export] F8 Challenger
340 (Currently in shop for stroker assy.)