Pimpium57

iTrader: (104)

....as opposed to going with the 4.10s. My LS1 is simply bolt-on for now, but I plan on doing H/C in the future (God knows that's a whole other story). I race the car often, both street and track. But on the other hand, I'm often on the highway with it, sometimes making long trips (2 hour+) every week or two. That being said, I don't want a lot of drone on the highway. Talking strictly performance, if I went ahead with the H/C and put a 12-bolt in w/ the 3.42s and some really sticky tires.....is that a reasonable setup for street?

And going further, if you had two identical cars (down to every last mod, including tires) with, let's say 400whp, except one's equiped with 4.10s and the other 3.42s...good launch for both, the whole nine yards...how much distance are we looking at between the two at the end of a street 1/4mi.?

Thanks a ton, guys!

-Jon

Tranzor

Well, it all depends on the powerband of your h/c setup. IMHO, with any h/c setup, I would strongly consider not only a 12 bolt or 9", but also 4.10 gears with an M6. For instance, I just purchased a TSP cam kit (TSP 231/237 cam), and the powerband of that cam is something like 2500-6800rpms. It would take forever to get into the car's powerband with 3.42s, and I'd be crossing the traps in 3rd gear... definitely not ideal.

If you stay with a cam that has a stock-like powerband, then the 3.42s would be fine... but since you're going h/c, I'm assuming your cam will end up being at least a 224/224, and in that case you would benefit greatly from the 4.10s.

Pimpium57

iTrader: (104)

What about the key factors of highway rpms and street traction? What type of cam only or H/C setup would be best then with 3.42s? Or is it truly best to go with the 4.10s, even with the all the highway use, etc etc.

-Jon

MyLS1Hauls

iTrader: (2)

There seriously is no reason to NOT get 4.10s in a 12bolt with a 6spd. I used to be able to get 30-31mpg stock motor with 4.10s on the highway. Traction even now is acceptable, you just have to roll into the throttle in first. 3.42 are a bad deal with H/C...first is just too steep. 4.10s also make 6th gear much better on the highway. I used to have to downshift to 5th to pass, but now I just lay into it in 6th. The final drive ratio of a 6spd with 4.10s is the same as an A4 with stock 3.23 gears, FWIW. I only turn 1900rpm at 70 BTW.

Tranzor

Yep... no reason to not get 4.10s, especially with a heads/cam setup. Hell, it's a great mod on a bolt-on only car. I really enjoy mine and would never go back... I commute to work at least a couple times a week in my car and highway driving isn't a problem at all with 4.10 gears. In fact, I'm still getting the same gas mileage as I was before the 4.10s.

rodent

iTrader: (1)

If I had to do it over again, I would of stayed with 3.42's. The QMP turbo kit has so much torque that I think 3.42's would of been perfect.

I always look what I'd like to be trapping at then look at the chart with RPM and different gearing. You want to go through the trap right before you have to shift.

Classic

iTrader: (3)

I ran 4.30 gears in my 9'' and they were just fine for the street. My choice was based on 1/4 mile trap speed. Honestly they were not bad on the highway either -- if I remember correctly around 2K rpms at 70 or 75 vs. 1600 rpm, not bad at all. Also, it gives you a real kick in the butt out of the hole (even on the street). Makes the car feel much more violent. Also, makes driving with an aftermarket clutch SO much easier -- say goodbye to clutch chatter. Also, your 6 speed basically turns into a 3 speed with the gearing. 1-3-5/6

VINCE

iTrader: (1)

It depends on your goals. I ran 12.28 at 116mph with the T1 cam and Mac Headers 3 years ago. With 3.42's, 275 inch drag radials, and a 2.0 60 ft.

If you are spraying a hefty shot I would stay with the 3.42's. Now I did switch to 4.10's when I added heads to my package. The car was much more responsive and streetable. I thought I would be shifting all the time, but that was simply not the case. The only thing that bothered me was driveshaft hum above 140mph and the fact my car maxed at 180mph in 5th..

mcflyz28

4000 miles and my Nittos are bald on the rear, probably why my rear is whining also.W/o a good heat up traction does not exist.