It has sentimental value. I understand that for sure!
Shortened version of a long story is that my dad and I started a build of a '75 Ford Maverick in the 1990's. I still actually have it. Dad always wanted that car to be somewhat "fast", and a 351w doesn't fit in a maverick front end without a LOT of work (and invented words). It was to be a race car from the get go, so I did a mustang II IFS in it as well. Dad wasn't much help. He got diabetes, or had it a while before and didn't know it-and lost most of his eyesight. So I finished it up (well as "finished" as a race car can be....). Runs 5.80's and a few 70's in the 1/8, makes dad happy, and quite frankly I don't need to go no faster in that car.
Mustang II IFS if it's installed properly works fine. Dangerous, only if installed IMproperly and/or poor workmanship or both. It's really hard to screw up a M2 IFS install, looks (based on the pics) that it was installed ok but I'd certainly go over it well. Mount the engine via motor plates; it takes a lot of load off of the M2 crossmember and adds some stiffness to the front frame rails. If the car is to have a cage (and it's suggested if you're going to go fast with it), a set of support bars out to the front frame rails would be considered mandatory, and not much extra work. Lastly is headers. Those will be a pain, probably custom. They're not too hard to make. It may be feasible to try a set of fox body swap headers, they might fit ok. Mine's a Maverick and custom engine location, nothing fits, so I made a set, actually it was a Stahl pro-gas A-arm "kit", which is already bent, all I had to do was trim and weld. Problem is, they will drag on anything taller than about 4", and occasionally coming off of a wheel stand.
Dangerous? Y'all never drove any of the old straight axle gassers. Y'all never drove an AA fuel altered either. Any altered for that matter. I have. You gotta be some kind of special to drive those money pits. Small time hobby bracket racer and nothing more now; and dad still loves watching, well mostly listening. So yes I understand the deal.
Go with it. It's your car, do as you wish. If you think your daddy would be proud of you getting it going, by all means do it. Value? Who cares. It's yours. Just like mine. I bet over the last however many decades, I probably have a hundred grand or better in mine, but it doesnt matter-I still dig it out sometimes, round up dad if he's feeling up to it, and head to the track, make a few passes, go home. Even win a few every now & then, but that's just icing on the cake.