I have a few questions about my 440 Charger with an 8 3/4" that is my daily, but I plan to bring to the strip once in awhile (and of course have fun at stoplights) First, has anyone ever seen a 741 pinion shaft cause any problems? I hear alot about how the 742 and 489 have bigger shafts, but how much does that matter? Second, if I am running 550 hp max, would I need anything to strengthen the rearend, and if so what? Third, in general what else would I need to beef up the car.(sub frame connectors?) I already plan on getting at least torque boxes. (Also, I already know half of the responses will be "get a Dana 60 or 9" Ford. I would only get a Dana 60 if it is cheaper than all necessary rear end upgrades)