Much easier ways to cut the fat.
Acid dipped cars will almost likely bend and twist beyond repair if dipped. The early 65'AFX cars twisted and could not close doors properly. They were crap in just a few short months.
You'll spend much more $ trying to brace it back to strength and that in itself will put back the weight that was removed.
Besides it being illegal to use certain acids in most states these days, when you do find a facility to perform it, they will not guarantee that the acid will be neutralized enough to keep the car from rusting into the earth again.
An A-body Dana car can be lightened to that magic number of 2800 with a few well thought out remedies. Aluminum, Lexan, Fiberglass, Carbon fiber, Titanium,(if you have those dollars burning a hole in the pocket), Inconel, Stainless steel and the list keeps going.
Remember, that a super light car may be it's own enemy when it comes to stability on the high end.