There really isn't a problem with coil over setups. You'll need ladder bars or a four link to locate the axle, and a panhard rod. Ladders are easiest, and great for straight line performance, but if you ride down a rough road you'll feel it more. Four link is best for ride. You'll need to beef up your upper shock mounts -- best to put in a cross member. The original shock mounts aren't designed to hold the entire weight of the car. Ladder bars can be made to use the front leaf spring mounts, four link needs new crossmembers for the links, might be able to use the lower leaf mounts though. Novas are popular enough, you can find a prefabbed back half with all the mounts, that's your best bet.
If coil overs are mounted at an angle the spring rate is affected. The advertised spring rate is only good for vertical mounting (which is most common for rear axles anyway). The greater the angle the more reduction to the spring rate. All this is in the Speedway street rod catalog, a great resource even if you're not into T's and 30s rods -- lots of stuff in there!