Sweet longroof! I'd personally skip the bags, swap the 305 for a 350 (SBC stuff is CHEAP these days), and drive the wheels off of it.
Its coil sprung all around or should be. Rewound springs in the rear and drop spindles in the front should do it just fine. I know a lot of guys that are really into bags. They were around back when that car was new. Personally of I wanted it to go up and down I would juice it. But that is just me and I am more of a static drop guy myself.