For at least the last 11 years, the rear axle ratio in Superduty pickups has been very limited. For SRW pickups with diesel engine, only one was available for '99 thru '07 models.
2010 SD V10 3500 DRW Crew Cab pickup. Problem is I want it with 4:30 gears for towing, yet $;30's are only available in Chassis Cab not pickup.
The order guide is clear. The V10 automagic dually pickup gets a 4.10 rear axle ratio. No options. End of discussion.
The SRW pickups with V10 have 4.10 std and 4.30 optional. The F-450 pickup has 4.30 standard.
My experience with Ford rear axle ratios is that they do a really good job of matching the axle ratio with the power and torque of the engine. For mine, the 3.73 is just about perfect as long as I use stock-size tires and stay within Ford's weight limits for my loads.
Back when the V10 had less power, 4.30 was available for DRW pickups. But with the power and torque produced by the 2010 V10, 4.10 is good enough unless your goal is to overload the tow vehicle.