[Z06] 3.90s owners
Thread Starter
Burning Brakes
Joined: Jun 2008
Posts: 768
Likes: 0
From: Lexington KY
3.90s owners
hey guys i have a 2002 z06 that i am in the process of modding. i have a vararam cai, vararam power duct, will be adding long tubes and a off road x-pipe in the spring. i have been thinking about doing a set of 3.90 gears after the exhaust. With the m12 i know i dont want to go with the 4.10s. I will be using DRs at the strip also. The car will be a street car that is taken to the strip a few times a year. Just would like to hear from owners that have done the 3.90 swap. How do you like/dislike them, how much did your gas milage change, how do the act on the street, etc. I dont want to start a thread about which gear ratio is better lol. Oh what other parts are required for the gear swap. Thanks
Race Director
Joined: Jul 2007
Posts: 10,961
Likes: 2,643
From: Texas Hill Country
What is your absolute final power level goal? Under 500 rwhp go with 3.90s. Over I would go with 3.73s. Mileage will go down 1 or 2 mpgs on the highway. The car will be much more responsive and fun to drive either way you go. Build your rear end at the same time.
Instructor
Joined: Nov 2001
Posts: 154
Likes: 0
From: Make it 3 yards motherf**ker and we'll have us an automobile race.
I think that you will be happy with the 3.90. How much power you will ultimately make is one consideration, what RPM you are going to spin the motor to is another. It will make 6th gear feel "usable" on the expressway. Fuel mileage won't be effected too much and the car will be much more fun to drive. I wouldn't wast my time with a 3.73 gear. If you will be making a lot of power in the future, just stick with the 3.42.
BTW, I am making too much power for my 3.90, so I will be going back to a 3.42 set up in the next few months. (C6 Z06 center section) I will be selling my DTE stage 3 center section with the DTE strut brace. Keep that in mind if are interested. Either way, I'm sure you won't regret putting 3.90's in your car.
BTW, I am making too much power for my 3.90, so I will be going back to a 3.42 set up in the next few months. (C6 Z06 center section) I will be selling my DTE stage 3 center section with the DTE strut brace. Keep that in mind if are interested. Either way, I'm sure you won't regret putting 3.90's in your car.
Safety Car
Joined: Jan 2006
Posts: 3,940
Likes: 43
From: shavertown Pa.
If your only going to do some fun racing, and your intent is driving the car all you can for pleasure, going to a stiffer gear is only going to take money out of your wallet everytime you fill up.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.
Instructor
Joined: Nov 2001
Posts: 154
Likes: 0
From: Make it 3 yards motherf**ker and we'll have us an automobile race.
If your only going to do some fun racing, and your intent is driving the car all you can for pleasure, going to a stiffer gear is only going to take money out of your wallet everytime you fill up.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.
With the 6th gear ratio in the transmission, it won't make too much difference on the expressway. Cruising RPM will only go up by about 300-400 RPM at 70-75 mph.
Le Mans Master
Joined: Feb 2001
Posts: 6,777
Likes: 358
From: West "By God" Virginia
CI 7-8-9-10 Veteran
I opted for 373's, I ended up finding a great deal on a DTE stage 4 373. I think they are the bomb diggity!! I do think 390's would be better for interstate blasts, but with 450whp na, and 550 on the squeeze I knew traction would be nill w/390's!! Traction is pretty bad with the 373's, first and second are pretty worthless, and third can get squirrly!!
If you plan on just keeping stock internals and boltons, I would go 390's!!
If you plan on just keeping stock internals and boltons, I would go 390's!!
Drifting
Joined: Nov 2004
Posts: 1,650
Likes: 4
From: Ringgold GA
If your only going to do some fun racing, and your intent is driving the car all you can for pleasure, going to a stiffer gear is only going to take money out of your wallet everytime you fill up.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Burning Brakes
Joined: Jun 2008
Posts: 768
Likes: 0
From: Lexington KY
thanks for all the replies everyone. i have had a couple of cars with 3.73s (auto) and one with 4.10s (5 speed). i am going with a ECS 600 Novi kit down the road and i think i am going to stay with the stock 3.42s. My lightning had 3.73s and 500+ rwtq and traction was just not going to happen on street tires lol. thanks again
Racer
Joined: Apr 2002
Posts: 339
Likes: 0
From: arlington va
If your only going to do some fun racing, and your intent is driving the car all you can for pleasure, going to a stiffer gear is only going to take money out of your wallet everytime you fill up.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.
Low gears are fun and make the car feel alive, but when you have to stop useing the interstate to go places, because the engine is screeming in 6th gear, there not so much fun anymore, I had a 64 with the 4.10's and a highway ride was out of the question.
GM selected 3.42's because it's a nice middle of the road gear.