I've heard that too... the residue from soda blasting will keep it from rusting. But you have to clean it off well before priming so the paint will adhere. Also have to sand the surface to provide some bite for the paint.... a soda blasted surface is too smooth.
For lots of other opinions, there is a great autobody forum at
www.autobodystore.comThe board moderator, Len, is in Jersey too.
Are you having the body shell blasted? It sounds like you have most of the other body parts already done.
FWIW, I sand blasted the entire interior of my silver 66, then DA sanded everything I could to smooth it out, and primer with epoxy. Did the same for the underbody. Firewall was in great shape, so it just got wet sanded and painted.
I gotta get back on that silver car.....as soon as the red one is on the road!