With the SRT-10, you already have 4.10 gears but also have a 31.6" tire. At 6100 rpm (approx. redline) 3rd gear = 108mph, 4th gear = 140. I don't see too many SRT's destined to run 140mph qtr. miles. Switch to a 28" tire and you get 3rd = 95, 4th = 124. Now we're talking. Actually with spray, I would short shift @ 5300 rpm in 1st-3rd, or 89 mph, and then let 4th go as far as it needs to. I would hope someday it's 124 mph.