1974 dodge dart swinger suspension ideas/ recommendations

The first thing I want to do with my 1974 Dodge Dart Swinger is upgrade my suspension.  I'm looking for any recommendations out there.  I'm not to excitied with the rear air shocks because they dont hold air for too long.  My front suspension is ok as long as i dont hit a bump.  When I hit bumps theres a huge knock, sounds like metal on metal.  I plan on replacing the bushings and shocks but am not entirely sure if that will fix my problem.  

The knock is most likely something that is worn or broken. You will want to find the source and determine what fix would be necessary before you have a catostrophic failure at speed on the highway. It may be a worn bushing and your planned replacements will fix it, but you should isolate the issue before you just start replacing part or teh problem may remain after you change out all the wear items.

As far as upgrades, what is your inteded purpose, budget, and expectations? you can get a mopar to handle very, very well for less than a couple grand and a some time, research, and effort. But, you don't want to go after $500 shocks and heavy spring rates if all you want the car to do is ride nice on the way to the show and shine and you only have $500 to spend on the whole suspension.