I know V8 guys who were running 5.38 gears on the street. In 4th gear across an intersection too.

If you're just concerned about straight line street racing, deep gears definitely help. But if you run at the strip, you need to figure out what gears will put you in the meat of your power band when you cross the finish line. I lost 2 mph trap speed in my Chevelle because I had to shift up just before the finish line, so I was going through at 4200 rpm vs 5800 rpm with my other gears. But I was also 0.3 seconds quicker so there's that.

 

Personally I wouldn't go higher than the 3.9 gears. Go out at highway speeds and keep the transmission in 4th gear, that's what your highway experience is going to be like with the 3.9 and it will be even worse with higher gears.

 

Thank you both for taking the time to respond to my random little post on this old thread. I decided to go with the Tomei TRAX 3.9 ring & pinion from Japan along with their 1.5 way LSD (an upgrade from my stock Z vicious unit). I also just installed Cosworth cylinder heads with JWT S1 camshafts and spent WAYY more than I was expecting too making sure the heads had the best hardware possible. Though the gears and 1.5 way diff. are not here yet, the Cosworth heads make a huge difference in every way possible. They were installed at the same time as I got Michelin Pilot Sport AS 3+ tires (255/40ZR17 rear & 245/40ZR17 front) and I can't wait until the gears & LSD kit are installed, also. I do not know about power & torque on a dyno but my car feels like it wants to throw you in the back seat in the best way possible already. It will induce a smile every time on these V8 snobs who live around me. Good to hear a C7 ZO6 owner say "that thing is an absolute monster. Be careful out there. Damn.. I still can't stop smiling."