what gear ratio is better for an auto daily?

302 auto c4 tranny. it has the stock 3.11 gears in it now but it doesnt have the greatest acceleration. i am looking for something that has great acceleration and still be a good driver on the interstate. i was thinking 3.73, 3.55 or 4.10 but i am not sure with the 4.10 i also would like it to be posi traction.. thank you

 

Stock were either 3.00 or 2.79.


for a mild daily driver go with 3.55's

 

If you have the stock rear end...It only has 2.79s' or 3.00s'... 3.55:1 would be the best bet for a 3 spd auto on a daily driver that sees highway use. taller than that and your RPMs' will be up high at highway speeds.

 

Check out this calculator:

http://www.rearendparts.com/pages.php?pageid=16

You need to figure out a desired cruising RPM (and your tire height) and work from there. Your C4 does not have overdrive, so you will be dealing with a 1:1 3rd gear. If you want to cruise 65MPH at 2500RPM, see what ratio would get you close to that with your 1:1 high gear C4.

I prefer lower cruising RPMs, so I would go with the 3.55. If you have a 30inch tire diameter, this would give you 2584 RPMs at 65MPH. Just play with it and see what you come up with.

Posi is doable, look for 8" trac-loc units on eBay.

 

really huh i read an article on 72 grabbers and it said all 72's came with 3.11 rear ends mybad on that part i was miss formed. i was either thinkin 3.55 or 3.73 b/c i had a 4.11 in a camaro and when i look it on the highway it always sounded like it wanted another gear.

 

Yeah, mine is an 8in and has 3.00 right now, im gonna go to 3.80 soon if i cant get my hands on a 9inch. like maverick75 said 3.55's would probably be the best if you want a little more of both worlds for interstate driving, but if it were me i'd go with 3.73 just for a little more "throw you back in the seat" power off the get go.

 

I wud say anything abv 3:55 to 1 - I wud be considering an upgrade to overdrive for daily use. IMO it's unrealistic to expect great acceleration and nice daily driver w/ C4 and 4:00+ series gearing, esp., if you are driving 60mph + for any distance.

 

A 3.55 gear is just about right for freeway cruising,and a little playtime on the track,or red light to red light fun.

 

i prefer 3.25s. 3.50s has the rpms a little to high for my comfort level on the freeway. i find that 3.25s gives you a happy middle ground. you can get up and go from the stop light nicely and still not be spinning the motor to the moon on the freeway. those are the gears that i put in mashoris diff and he was very happy with them.

 

where do yall get 3.73 gears at??? all i find are 3.80's :/

 

3.80s are what is avaiable for the 8". 3.73s are very common for lots of other diff types. the difference between the two ratios wouldnt be noticed.

 

Agreed. 3.25 is a good compromise, 3.55s turn too many rpms at 70 mph IMO.

 

I think 8" gears are 2.79, 3.00, 3.25, 3.55, 3.80, 4.11, and 4.56.

I have 3.80 and they are just barely decent on the highway. If I did any more highway driving, i would go 3.55, but I do a little drag strip runs so I sacrificed highway gears for 3.80.

 

IMO...355 is a great gear for these cars. Might be a little high on the RPM's for freeway but just slow it down a tad and enjoy the ride. But for back country roads and around town 355 works great.

 

Mine runs 4:11's and turns 3200 on the HWY to work. Noisy but sure is fun off the hwy. I prefer the country roads to work anyhow.
If I had my choice I'd go 3:55 C4 or keep the 4:11's and go AOD.