245 is a lot more tire than these cars came with. If you're trying to get down the drag strip, there are slicks in that size that will do the trick. Personally, I'm not a fan of tubbing a classic car unless it's a really serious build but it's your car of course. :)
As for the bubbles on the torsion bars, is it just paint? Pitting/rust in the metal could be a safety concern. Why were they painted to begin with?
The sway-a-way bars that I have are powder coated but I'm pretty sure they're usually bare. Maybe someone can correct me on that.