I have a 91 camaro rs with a 305 tbi a 700r4 and a stock non posi rearend. the car has 81xxx miles on it. i 50/50 street/highway driving and occasional track dragging. would you reccomend a 3.23 posi rear or a 3.42 posi rear(both from 4th gens) would like similar gas mileage as now. but would like to take some time off 1/4 mile times and quicker launches

 

3.42, i have 3.73s in mine for DD and like em

 

I've run both of those ratios behind my 305 TBI/700r4, and either of them work quite nicely. I'd have to agree with the above post and give 3.42's the edge, especially for quicker acceleration. I thought it would kill my gas mileage when I switched from 2.73 to 3.42, but it really didn't affect the mileage that much at all. I even took a long freeway trip not long after the swap that I had driven previously with the 2.73's, and I managed to make it to the same gas stations before having to fill up again. I'm running 3.23's in it now, and they work pretty good, but I kinda miss the 3.42's.