So I was initially elated to discover that someone makes a disc brake kit for the 3/4 ton 8 lug Spicer axle now:
Ford F250 (8 Lug, 3/4 ton) 4×4 front Drum-to-DISC BRAKE CONVERSION KIT, Dana 44 (w/Closed Knuckles) Fit 3300 LB (or Less) Front Axle Only. – Horsepower Sales, LLC
However... the $1600 base price has me rethinking it. The Spicer 44 isn't a particularly desirable front axle. For the price of just the brake kit, I could probably swap to a later model, open knuckle, disc brake, high pinion Dana 44. Opinions? I don't need the strength or servicability of the HP Dana 44, but I do plan to swap in a ZF5, so I think disc brakes would be a nice safety upgrade. What are the primary safety concerns running drum brakes at freeway speeds? Should I first try installing a dual-chamber, vacuum boosted master cylinder?

 

Generally speaking, drums work as well as disc- along as they properly adjusted. There’s some advantage to mudding/water crossings in favor of discs as well. But it’s the maintenance of keeping them in adjustment that always pushes me to disc. I guess what I’m saying is if you can find the right axle and you’re not trying to stay stock, swap it.