Bigger tires will help the RPM situation. I've run 255/85x16 tires on the rear and those are about the same rolled radius as the original 7.50x17. Zero offset alloy wheels are the ticket here or Ford steelies. There are also larger 19.5 tires that may have a lower revs per mile. Those wheels can be had with the 8 on 6.6 bolt pattern. You'd have to look around. Tire rack used to have a good source of information like that but they were bought out by Discount Tire a couple of years ago and some things disappeared from their website.

If your drums are not out of spec you should have no trouble selling them to defray some of the cost of a modern 14-bolt axle if you decide to go that route. Also bendix brakes can be found to fit the HO72 axle that you have. Big tires with a 4.57 final ratio is a reasonable compromise. I found one out of a 67 3/4 ton manual trans model.

1951 3800 1-ton
"Earning its keep from the get-go"
In the DITY Gallery
1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.