What does “underdrive pulleys” mean? What is the ratio?
For your original setup (no radio) you should have at least a 2:1 alternator ratio with a 60-70 amp alternator. On my car I have a March 5 1/2" Crank Pulley and 2 11/16" alternator pulley. I have 9000 mile on my car with this setup and all is fine. No radio in my car. I would consider this minimal and may not be enough if you do a lot of idling below 1000rpms. Adding a standard radio should not add much draw, but if it also has a high powered amplifier, the above may not be enough. You may want to consider a larger amp alternator and/or a higher alternator drive ratio.
The one wire alternator is a simple installation. You simply only hook up the one large wire that goes to the battery. You can also hook up the wire to the red alternator light on your dash, but it is not required for proper operation. All other wires can be removed or taped and tucked out of sight. Remove the regulator and those wires can also be removed or taped and tucked out of sight.
There is no need to go to a $850 alternator. The alternator mentioned by Bill Wells at
http://performanceunlimited.com/cob...lternators.html is plenty.
Oh, and just for the record… All this has nothing to do with Superformance, as the thread title may lead people to believe. Superformance sells cars, not powertrains (or alternators). This is an engine installers issue.
Good luck
Craig