Does anyone know who manufactured this Mustang II suspension and if there's an option to use regular springs with this setup Thanks
Do you have a pic of the center crossmember? You can use regualr springs but would have to modify the lower spring perch.
You should try and get a full shot of the X-member. I can tell you this,those lowre control arms are set up for air bags.You would have modify the center plate for coil overs,or cut it out and weld in the proper spring pockets for coil springs and shocks. As for the manufacturer,your guess is as good as anyones.
I'd check with some of the manufacturers, (Street Rod Engineering, TCI, Heidts, Jim Wymer and others) and email these pics to them with some accurate measurements. I'm pretty sure you will need to replace the lower control arms if you want to run coil springs rather than weld in new spring pockets. I've fussed with the springs on my '40 a couple of times and still don't have it right. I think if it were I depending on what vehicle your working on I'd go with the air bags.
TCI judging by the anti-roll bar. A simple swap of the lower control arm would get you where you want to be.