gerard14

1995 z28 with some mild mods, t56 manual tranny. whats stock 3.42's? anyways if i switch to 3.73's how much will gas mileage drop?

is first gear gonna be so annoyingly strong it spins the tires all the time??

say in 6th gear cruising at 70 how much will rpm increase vs stock gears?



does motive 3.73's require an install kit also, or will the pinion and ring bolt right in?

97FormulaWS-6

It's not tire-shreading performance, it will get you out of the hole quicker, and gas milage all depends on how heavy your right foot is and how agressively you drive.

But to answer your questions:

No, it's not that low, although the ability is there if you want to shread your tires if you are not running a sticky tire.

I run about 1900 rpms at 70 mph, give or take the accuracy of the stock tach.

I would suggest the install kit as well as replacing both wheel bearings and seals, you've got to take the whole thing apart anyways, might as well replace all the parts and start with a fresh axle.

MarkyMark

most 6 speeds go to 4.10 gears.........going from 3.42 to 3.73 is kind of a waste of money and time.

heliskiier1

Diasgree with Marky...the 342 to 373 is a nice seat of the pants boost and you won't have to buy that 12 bolt quite as soon. Love my 373's. I'm a streeter, no strip. Most of the strip guys will do 411's but remember you'll be shiftin that thing endlessly on the street. When I get my Moser, the 411's will go in...(i.e. when I come up with $2 grand for the Moser!!!

Mine's at about 2 grand and 70. Highway and city mileage almost unchaged with the M6. 14-17 city and 24-27 highway. Can't wait to see what happens when the Procharger goes on next week!

mudkat]

stallion114

From what ive heard you wont regret 410s in an M6

94formulabz

I personally know 2 people who did.
I will acknowledge that there are a lot of 4.10 supporters out there thoguh.

To the original question, no first won't be too strong, as stated most people go with 4.10s. I personally ran 3.73s for about a year and really liked them. I've since gone to 3.89s and feel they are absolutely perfect for a 6spd car that sees the highway. Since you don't have the option of 3.90s in a 10 bolt, i'd recommend erring conservatively and sticking with 3.73s since your concerned about mileage. It is a nice noticeable change.

-brent

EviLZ28

I had 4:10's in my 6 spd Trans am. I liked it at first but then soon got tired of it and it really was bad when I added Nitrous. Talk about alot of shifting. 1st gear was gone instantly. I then dropped to a 3:73 and was alot happier. I now am putting together a 9 inch and I will be running a 3:90 gear.

D James

I guess it depends on your goals, I found it easier to launch with 4.10s in fact my 60 ft improved consistantly over the 3.42s. You must feather the gas at first than let into it. As far as shifting to much-I hear people say this all the time, doesn't make sense to me, afterall I have to shift regardless of what gears I have. I will admit first and second go much faster, but for the street its so much more fun and faster. If your granny shifting and worried about having to shift more often, than just do as the car was intended--skip shift 1-3-5, 1-4-5 this will give you better gas mileage than 1-2-3-4-5 Hell I would go 1-2-5 as well. My rpms are right at 2500 rpm at 95 mph, thats plenty low for such a fast speed, and even then its still faster than what I normally travel According to this calculator http://www.f-body.org/gears/ at 71 mph with 342 gears is 1600 rpm
70 mph with 373 gears is 1700 rpm
71 mph with 410 gears is 1900 rpm
70 mph with 456 gears is 2100 rpm
The last would be my favorite gear, but to much for the 1/4 and probably would get some whine with it, anyway your only talking 300 rpm more than stock. I keep track of my mileage and it didn't drop at all, stayed right in the average, unless I was very hard on it, which made the mileage drop more than the 342 gears, but not that much worse. In fact because the car has more torque to the rear wheels you could get better mileage-just slightly of course. The torque is one good reason why our cars get great highway mileage to begin with, it lets the car pull that .50 6th gear double overdrive. The Honda S2000 with its smaller engine is actualy rated lower highway mileage than our cars,- I think 26? and one mpg more city than ours which makes since since it is smaller engine and lighter car. As far as breaking the rear, it might break with stock gears. I ran mine at the track with a cam, SPEC II clutch and stock tires, and no problems, the guy that had the rear before me ran at the track with Nittos, so they can hold up sometimes. How does it feel? Well 2nd gear now feels like 1st gear felt with stock 342 gears
By the way the installation of my cam made the gas mileage drop the most of all mods I did.

Janny

I've got 3.73 with an M6 and I really wouldn't want a steeper gear. First is usable, but you're pretty quickly out of it. I can only imagine how useless 1'st must feel with the 4.10. Stab the throttle. Grab a gear. Or, hook a chain on the car, put it in 1'st and start pulling tree stumps.

gerard14

nice post Djames