Yep, it totally depends on what the ratios are. Lower numbers (2.7, 3.0, etc) are more of a highway gear. Better gas mileage on the freeway, but acceleration is slower.

Higher numbers like 3.5, 3.9, 4.11, much quicker off the line, but not good on freeways.

Ratios are kind of confusing. Lower numeric numbers equals slower engine speeds compared to a higher ratio at the same mph. Wild butt example, going 65 with a 4.11 ratio you might have an rpm of 5k. With a 2.75 it might be closer to 2K. Hope that makes sense. Those numbers are not real, but they do give you an idea of what I am talking about.

You have to know what both rears have to compare. However,odds are you could buy the same ratio gear for the 8 inch rear as what the 6.75 has if you like the current ratio. Lots of available ratios for the 8 inch.

What it all really comes down to is how do you want the car to be? A stoplight to stoplight cruiser is fine with something like 4.11s, but without overdrive not great for hoping on the frewway for a long trip. And vice versa, something setup with 2.75 gears is not much fun off the line, but great for long distance freeway driving. Something in the middle will give you some of both worlds.

Russ