Something small like the Mopar 528 cam and a "Hemi" converter should take care of it if you aren't going racing. For street driving you just want the converter loose enough that it doesn't push you when you are at the drive thru lane or a stop light. If you have a small performance cam like the 528 you'll have a slightly raised idle speed so you'll need something a little looser than a stock converter. Idle speed might be 900 rpm with the 528 so you'll need a converter that lets it idle okay but you still want it "locked up" when you are cruising down the freeway at 2000 rpm.