So here's a question. Currently my 1967 Dart has a 7 1/4 with presumably 2.93 or worse gearing. I bought the car with American Drag 15" rims, so my guess is that an already lousey gear ratio is made worse by the tire size (which I actually like on the car). My question is, that ideally, I would like to have 3.73's or so, but I haven't seen any ring and pinion sets for that rear diff. available. What I have seen, is 4.10's. With my increased tire size, would 4.10's be reasonable end result? The car also is an automatic with 904 and 273 motor. I'm planning on camming and carbing the car in the near future. I'd like the car to be snappier off the line, and I'm not really planning on using the car on highways much or at all. The car only has 36000 original miles. On another note, If I decide instead to try to find an 8 1/4, what is the easiest model to look for to swap? If I've read correctly, try to grab one out of 91ish Dakota (?) I think. Is that an easy swap, or do I have to reinstall the leaf mounts etc? Thanks for any advice.