225/70/14 is a pretty dinky tire for a charger like yours. Won't take much to blow those away. I'd suggest something more like a 275/60/15 which is what I run. Anyway, are you willing to upgrade to an aftermarket higher stall torq converter? Comming from someone who's been there and done this already, I highly suggest you spring for a torq converter in the 2600-2800 stall range.