how loud is your stock radio

It should be fairly loud. That said if it is a factory radio it will have "Dart"/"Valiant" or "Chrysler" on the dial face. If it only has "All Transistor" or "HI-FI" on it it is most likely a dealer install after market radio-which is just as loud as the factory radio. Very common is the speaker bakes in the sun and is no good now. Radio shack use to have cheap speakers to replace them with. Also very common is no one adjust the "ant trimmer" on the radio which will make for weak reception.