I'am sorry to bring this up again, I've read all the threads, but can't get an accurate answer. I'am trying to deside between either 3.42's or 3.73's, anything else is either too big for sure or to small, and I have 2.73's right now. All I want to know is people w/auto's rpm at 65ish w/either 3.42 or 3.73's????? Right now my RPM is 1800 exactly at 65mph, just need an exact answer, that online gear calc. thing is wrong, I put my car in gears in there and it was 200rpm off. Also anyone with gear swicthes from 2.73 to either of the two you opinions would be great. I really want to know if 3.42's are even a noticeable difference over the 2.73s(which suck by the way, ).

Thanks in advance for all your help.

 

3.42 is my vote

use this: http://www.f-body.org/gears/

 

3.42's get my vote too if its street driven a lot. I went with 3.42's and I'm glad I didn't go any higher because I drive on the highway 75% of the time. I'm not really sure what I tach at 65mph. At 80mph I tach about 2500rpm.

 

I went from 2.73's to 3.42's. It's a definite improvement. IMO I'd go with 3.73's if your keeping your car NA, or 3.42's if a power adder is in your future. Also I'd go with 3.42's if the car is your daily driver, or you drive alot on the highway. Overall I like the 3.42's in my car, but I'd go 3.73 for a max effort NA car.

 

Dead on..at 65mph you should tach ~2050rpm

I love these gears. Good pull in triple digits.. .decent street performance (Light to light) and I can still roll the interstates without sucking down the gas. Love them.

 

Yep, I just used the calculator and it shows exactly what I tach at 80mph even with the old 3rd gen tach.

 

my calc shows 1920 with 3:42s and 2094 with 3:73s ant that is showing 1600 with 2:73s. but your stock tach reads 100-200 high, Just today i make about 10 WOT runs as we were tuning my car and the tach reached 6500 on the 1/2 shift every time yet the computer said the highest rpm it reached was 629X every time.
The computer is right, the tach is off.

As for which to chose... to any car running 11s or higher i say 3:73s. you start going down when you get into the 10s and run out of greas in the 1/4.

 

Exactly.

 

I like my 3.42. Can't tell you what the difference would feel like though, they were on when I got my car. IMO I would go with the 3.73. From what I've heard on the board, gas mileage shouldn't be affected that much.

 

I have a stick but I can positively tell you that the stock tach is WAY off. I have an autometer tach that is a lot more accurate and if you have freescan it is accurate to the nearest 25 rpm dead on.

 

I goota say to go with 3.73s, they're not too bad on gas, and the car is daily driven.

 

The car will definetely be daily driven. I guess the fbody gear calc is accurate, I was assuming that the stock tach was correct, but i guess its not, according to it, its a 400rom jump at 65 for 3.42's but only a 600rpm jump for 3.73's, so im thinking that the 3.73's should be that awfully to big, gas mlg is a for sure a problem if its bad...as im a ***** lol. Anybody with mileage number for either a 3.42 car or 3.73 car w/an auto would be great????

 

I usually get about 21 mpg, mix of city/ highway.

 

I went from 2.73 to 3.42 then to 3.73. I'd go with the 3.73's as the car really wants to accelerate and the gears are quicker and crisper. With the A4 shifting at WOT the 1-2 shift is 3000 rpm and the car just goes. The 3.42 was more labored with the shift being at a lower rpm. I do a lot of highway cruising so I had the BF Goodrich Radial TA 265/50/16's put on the car. They're an inch taller than stock and give 5mph more per given rpm or 200 rpm less per given speed. These tires are only S (112 mph) rated but really how often do we go faster than that for any length of time. Overall a good combination if you like cruising at 90 (3200 rpm) yet want great 1st gear.

 

I've got 3.23's now, and I'm thinking of getting some new gears too. I'll have hotcam, ported heads by lloyd, 52mm tb, hooker LT's with custom 3" exhaust. Do you think 3.73's would be fine or just go with 3.42's. Thanks.
JOHN