Will the Dyna S work in early Panhead applications with reverse rotation distributors?

Yes the Dyna S works in these applications extremely well. Just remember that in these reverse rotation applications that the front cylinder becomes the rear for ignition purposes. When using the DS6-2 single fire, simply reverse the black and white wires. With the DS6-1 dual fire, simply use the rear cylinder timing marks. Some modification to the mounting plate may be necessary for proper clearance.