How much gain from 4.11's?
 

Well the 4.11's are being installed as we speek. What kind of gains should I see from them? Will my MPH drop? My best is in my sig with the stock 3.42's.

TIA
Craig

13.64@105.1mph // Just a guess.

I gained a consistant 2 tenths on average. I imagine 4 tenths could be had. It makes a pretty big difference in performance. Its real hard to hook up, although I found my 60 ft improved slightly-which might be attributed to me getting better at launching-not really sure. My MPH dropped 2 but then again that day everyone was down a little because of the crappy weather.

How come I see 4.10's and 4.11's in these peoples Sigs? I mean which gear fits into our stock 10 bolts? (LT1)

I gained a little over 2/10's and 2-3mph when I went from 3.42's to 4.11's. Plus I became addicted for a while to doing 0-60 runs after installing them :D

Ratio wise they are basically the same, it's just the difference in the teeth used on the ring and pinion gears:

4.10's = 41 teeth on the ring gear and 10 on the pinion (41/10=4.10)

4.11's = 37 ring / 9 pinion
(37/9=4.11)

4.11's gears are slightly stronger from what I hear since they have fewer teeth and those teeth are larger than those on the 4.10's.

yeah, what he said. I would go with 4:11's