When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Looking to swap gears in my 02 M6 Formula. Spirited street use only with the following mods...
Texas Speed and Performance Stick 4 cam kit with HP Tuners tune, Kooks SS headers and Y pipe, SLP Loudmouth cat back, Cai setup with ram air, Hurst short throw shifter, full complete BMR suspension with Bilstein shocks and struts, I have a fidanza aluminum fly wheel with a Macleod clutch set up.
I am looking for information to determine weather I'm going to go with a set of 3.73s or a set of 3.90s. I already know I'm not interested in 4.10s. Any advice based on "actual" ownership experience is greatly appreciated. Trying to figure out if there's a huge difference between the two. Is there a minimal difference between 373s and going up to 390s?
Please do not suggest 4.10s. I've already had them and do not like them. They are too short for the street. I am trying to figure out what is a nice compromise between 3.42s and 4.10s. I'm either going with 3.73s or 3.90s. I'm looking for some information on the difference in length between the shifts between the two. Tia
Agree 100% that the factory 10 bolt is not worth sinking a dime into, especially if you have a M6 and engine mods (unless you want to run skinny tires in the rear w/ no traction). It WILL break and you'll be wasting any money you sunk into it when you eventually are forced to replace it with a rear that can handle it.
As far as ratios are concerned, I think it depends on the rear tires you plan on running. If you have sticky tires, a higher ratio is better since you can put more of that torque to the ground. But with factory sized street tires, what is the point of using such a steep ratio that you can't even get to WOT in 1st gear without spinning? My stock LS1 was 1st-gear traction challenged w/ the stock rear (3.42), so I chose 3.73s in my S60 instead of 4.10s since I don't plan on running tires any wider than stock (275s). Sure enough though, I can't reach WOT anywhere in 1st gear without spinning.
Last edited by JohnnyBs98WS6Rag; Dec 24, 2023 at 06:30 AM.
Agree 100% that the factory 10 bolt is not worth sinking a dime into, especially if you have a M6 and engine mods (unless you want to run skinny tires in the rear w/ no traction). It WILL break and you'll be wasting any money you sunk into it when you eventually are forced to replace it with a rear that can handle it.
As far as ratios are concerned, I think it depends on the rear tires you plan on running. If you have sticky tires, a higher ratio is better since you can put more of that torque to the ground. But with factory sized street tires, what is the point of using such a steep ratio that you can't even get to WOT in 1st gear without spinning? My stock LS1 was 1st-gear traction challenged w/ the stock rear (3.42), so I chose 3.73s in my S60 instead of 4.10s since I don't plan on running tires any wider than stock (275s). Sure enough though, I can't reach WOT anywhere in 1st gear without spinning.
Ole boy said, “for spirited street use only.” How common is it for a 400’ish or less rear horse car to break one from a roll? Fairly common? Do the road course guys upgrade rear ends too? I suppose the big power boys probably do. But what about the 400 ish horse guy? Would he need to necessarily? A road course car would be a closer comparison to a street car than a dragster would. One might race from a stop light now and again maybe (bad idea. not safe) but surely it wouldn’t be a huge clutch dump and it’d be on street tires. If one takes “the launch” out of the equation how well does the 10 bolt hold up? Are they breaking shifting from 3rd to 4th etc at moderate power levels?
I wish there was a better option for the street car crowd than to have to expect to have delete ABS/TCS and live with dash lights after spending that kind of money. It’d also be the pits to end up with a loud one or any other issues that seem to happen more than they should considering the price tag. It’d also be the pits to get a loud one. @Mezzy If you didn’t like the 4.10’s I bet the 3.90’s might still feel too short. I once went from 2.73 to 3.73 then “down” to 3.31’s in a car that has a trans ratio as follows: 3.35 1.93 1.26 1.00 0.68. And I believe your T56 is: 2.66, 1.78, 1.30, 1.00, .74, .50.
For me the 3.73’s were too steep and they got a little old after awhile. The 3.31’s are a more “comfortable” gear and the car isn’t much if any slower really. It’ll still burn rubber from a roll and the highway cruising is much improved. However, the 3.73’s worked better with the cam at parking lot speeds than the 3.31’s do. If your cam doesn’t require a mega steep gear maybe take a look at the 3.55’s. Remember when we’re talking gears we’re talking about fractions of a second on a race track. To all the street car guys: A hundredth of a second won’t make or break you on the boulevard 500, but running down the highway at 3k rpm might break your sprits down the road a ways. Drivers age depending of course. 😂 3.55 gears but not a specific brand recommendation
Last edited by Y2K_Frenzy; Dec 27, 2023 at 11:39 AM.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
Gearing Help 
