Your '75 would have a Dana 44 from the factory, so that opens up some options.
If you're not sure yours is still so-equipped though, it would be good to verify.
Most setups in "kit" form are going to be about the same as far as number of parts and installation time and procedures.
You can do it three basic ways:
1. The conversion that most of us vendors offer (fits both the D30 and D44 front ends) using a combination of Ford-based and GM-based parts. Vendors or junkyards.
2. The Ford-only conversion (only fits a 44). Duff or junkyards.
3. The purely aftermarket, such as the Wilwood kits shown on the following page:
Wild Horses Front Disc Brake Options along with the GM/Ford hybrid kit.
I personally feel you don't "need" a power assist to make disc brakes work fantastic. But as usual, it depends on what's under your rig and what you are looking for.
I've run non-boosted disc brakes for years and love it. Don't feel the need for it at all. But I also have modest sized tires and (apparently) good pad material.
If you're running 35" tires or larger, or just like the feel of modern brakes over old, then a booster is likely in your future. But at that point took, I think it's pretty well accepted around here that spending the extra on a hydro-boost is worth the upgrade over the vacuum booster.
I have not run one myself, but it's almost universally acknowledged as the more powerful option. If not also more work to install.
If you want to stick with manual, and have 16" or larger wheels, the larger diameter rotors and larger calipers with smaller, but more pistons calipers offered by Wilwood are another option. Or even if boosted anyway, they're still an option for more powerful brakes.
That's a bit of the nutshell version. I may sell be trying to sell our kits of course, but I don't believe there is really much of a difference from a quality/installation/difficulty standpoint between the different hybrid offerings.
Paul