anyone ever seen airbags on a 70' valiant?

Nope. Since Mopars use torsion bars instead of coil springs, there really is not enough room to install an air-ride type suspension in the front. The rear is simple enough, as it's just a standard leaf spring setup, but the whole front end would need to be re-engineered to accomodate bags.

I've seen Hydraulics on ONE MoPar. A '70 Newport...He had to hack out the inner fenders to do it, and it resulted in a cracked frame rail...Not Pretty.

I've seen Air Bags on ONE MoPar, a '67 Newport that was at Spring Fling in '00. He removed the inner fenders, too, and had what looked like a strut-tower brace welded in with the bag setup. Didn't look like a single thing up front bolted in. TONS of torching and fabricating, though.

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"When applied at precisely the right time, Ignorance is a powerful tool, usually even surpassing knowledge" E.J. "Michigan Madman" Potter.

The coilover K-member that bigblockdart sells would be good candiate for the airbag treatment. It is based on the Mustang II. And this K-member is a bolt-in.