I ran a 600 Edelbrock carb with electrhttp://www.edelbrock.com/automotive/mc/carburetors/performer.shtmlonic choke on mine. Other well tell you to run a Holley. It is really up to you, but no more the 750 CFM unless you have other modifications on your motor.
You will also need a 4 barrel throttle cable bracket, as the 2 barrel one wont fit.
As for cleaning and painting/polishing, again it is up to you with what look you want. I cleaned mine with a good degreaser and painted it silver to match the original finish of the LD4B, or you could paint it your block color. If you want it polished it would look good as well.
Another tip...check the carb stud holes in the manifold. A lot of times the have been striped out. Run them with a tap, and if needed you can Hilo Coil them.
You will like the performance increase and drivability you will get.
