Yes of course there is. The 1973-1977 Bronco power steering box is native to the application.
It is a derivation of the Saginaw 800 series Gearbox that is used in every GM steering box used in the late 60's thru the 90's. The difference in the gearbox is the mounting housing. If you look at your manual box, you can see that the pitman arm is located OUTBOARD of the frame rail. This is unusual, since most frames are wider, and the pitman arm is located inboard.
There are a number of various steering boxes used with an outboard sector shaft. The 76-79 F150 4x4 box, the IH Scout 2 box, and the Nissan X-terra boxes are all outboard as well. The Jeep wrangler JK steering box is an inboard sector box, but if you source one from a Mail Jeep, (RHD) you can use the passenger side inboard box as a driver's side outboard box. All of the steering boxes that are not Early Bronco require some kind of modification for mounting since the holes are wrong. And some kind of input shaft mod. And some kind of steering hoses.
After 30 years of successful implementation, the Saginaw 800 series gearbox was re-designed for the 1999 Jeep Grand Wagoneer. This new box is called the Delphi 670 gearbox. The control valve design was improved, and the box was successfully used in the Jeep, and some GM SUV's. It is more compact, strong, and steers better. The aftermarket realized the potential of the new Delphi 670 for retrofit into many different classics, and collaborated with Delphi to make housings to fit. This "new" configuration is called the "Delphi 600" box. That has become the "go to" replacement as it bolts to the bronco frame, and fits within the factory space.
Unfortunately, there are two generations of factory steering box for the Early Bronco. And for 40 years, they were coveted, swapped, sold, and cores were unavailable. So supply shrank, and cost went up. The year split is 1975 to 1976. The 73-75 boxes are vague, sloppy, and have ~6 turns lock to lock at the wheel. The 76-77 box is vague, sloppy, and has ~4 turns lock to lock. If you can find an original 76-77 EB 4 turn box, that is not worn out, it is an excellent steering box that will bring you many years of joy.
And with the advent of the "stronger" 76-79 F150 4x4x2 box, and the release of the superior feel Delphi 600 box, the old legacy Factory Saginaw boxes have stabilized in price, and are still out there.
The Xterra box is the closest but if going that route, I suggest the Borgeson box. I've been running it for years.....no issues with 33's and street driving. If bigger than 33's, the 4x4x2 custom box is an option. It's overkill if not running bigs and hitting the rocks.
