And clean the hell out of the battery terminals while you are replacing the battery. Pay attention to the condition of the battery ground cable where it attaches to the fender.

If the ground cable looks really bad, change it as well. You can get a generic cable at AutoZone, etc. for $15 or less. Consider doing James' mod when you do this, read this entire thread:
https://www.crossfireforum.org/forum...le-engine.html