I wanted to know what rear gear ratio the high boost guys are running and if the setup is for street or track. Right now I have a stock 10 bolt with 3:42's that's perfectly fine on the street but I have a 9 inch with 3:70's that needs to be built. I'm gonna put that in when I get all my other projects for the car knocked out but wanted to get some opinions from experience which gearset would be best.

 

Manual or Auto?? If it's a manual 6sp and you are running big DR's you can run 4:10's like I am. My speed at 70mph is 2200rpms if you are running an Auto run no higher than 3:73's or you will be screaming down the highway.

 

I can tell you that 4.11's in a 4L60E are horrible. 1st and 2nd gear are useless even with 27" slicks and I can't cruise too much over 55 or 60mph. They were supposed to be 3.73's which I think is still too much. If I were to do a gear change, I'd probably do something in the 3.20-3.40 range.

 

I have a 3.42 but I think I could go less. Some of that is because of the ridiculous 1st gear in the 4L60E. Last time at the track I trapped at 126 and was at the top of 3rd gear, which isn't too bad. I don't use slicks and don't get good traction, but I don't have a drag car, either. I am considering a Gear Vendors OD if I can prove to myself that the electronics will work. Then if that works and maybe go with a 3.08 gear.

 

I have a 6spd and on my last setup N/A I had 4:10's and even with 400rwhp 1st and 2nd were useless on the street. I should be seeing the track often next season but this is mainly going to be a street car so I want to be able to cruise around and enjoy the ride. With that being said should I be looking for somethin more like a 3:08 or would the 3:70's be fine, I'm pretty sure the power is gonna be there to make up for the lack of gearing on the track but I figure if I wanna turn it into a street strip car I can just get another third member with 4:11's and swap it out when its GO time.

 

My initial setup was 4.10's with the turbo. Kinda helped with any turbo lag on the street but I never raced at the track with that setup.

I then opted for 3.55's (I have a Ford/GM 8.8 hybrid differential) and it's great for an all around street car. Not much fun at the strip though since the 275 Nitto DR's either spin or bog. I sometimes drive long distances in the car with the 3.55's and it seems like it's at a fast idle at 75mph

I have a TH350 to put in it after I get the torque converter restalled to 4,000. I'll know how well the combo works at the strip next Spring.

 

Thanks for the info guys after reading what you have to say I think I'm leaning more towards having this an all around fun street car and when or if I do hit the track I'll have a race setup ready.

 

i heard once that 4.10 gears (w/ a 6spd) makes a forced induction car slower at the quarter.

it does this because you end up with an extra shift and with every shift you 'blow off' or waste your boost.

Not sure if this was urban legend or truth.

3.45:1 to 3.73:1 (w/ 6spd) seems like the best rear end ratio to have.

 

3.42. ....... Let that boost work for you