I was wondering which is the best choice of axle gears to get good 1/4 times and also be able to be pretty quick on the highway?

As far as I know- 4.11's would be too high and 3.27's are to low

What about 3.89. 3,73 or even 3.42?I would definitly want posi-traction

Any opinions would be great as I have a somewhat limited knowledge of rear axles/gears.

 

It all depends on your setup and what your looking for. I have a set of 3.23's and get good highway milieage with the motor in my sig. Of course I have an auto. Standards are geared higher in the first place so I would say having 3.73's with a standard (5spd) would be comparable to 3.42's or 3.23's. 3.73's in an auto is pretty low gearing, I had those in once, I would cruise around 2500 + rpms on the highway, so you may want to leave those out of the question. I would recommend 3.23's for overall compatability. Anything at or above 3.73's (especially with an auto) is just impractical for every day driving IMO.

Later
-Ben

 

Sorry, I didnt fully read your post, just kind of skimmed it. You want 'quickness on the highway', I was thining mileage. You'd still be quick on the highway with anything in between 3.23 and 3.73, but you have to remember also (assuming your auto) that your tranny will downshift at 2/3 throttle, meaning you wont be able to get a very high mph. Unless you get one of those kickdown elimination kits for your trans (assuming also a 700R4).

I'm just saying, you should take this into account also when deciding.

 

If you have a stock thirdgen than 3.42's are better for T-5 cars and the autos like 3.73's. This has been track proven fro many board members. Now once you start adding heads or a huge cam your RPM range increases and you can use a higher gear to get you into the powerband of your new cam. Many things to consider. For a daily driver, with stock or mild cam. A 3.42 is probably the best.

 

Sorry I did not specify that the car is a winter project and will have a 6 speed, large cam and either vortec or fast burn heads. I was leaning towards 3.73 but something tells me it should be higher. More than likely not a daily driver but a summer car

 

Well this changes everything. With a t-56 and a big cam 4.10's are perfect. Tons of LT1 and LS1 guys run them because they have that big 6th gear to cruise in. 4.10's and don't look back.

 

assuming this car is long tube runner tuned port injection and even with runners, base etc. the power band will not peak high enough to need a gear numerically higher then 3.45. its not pratical to run 3.73s and up in our cars. it takes some pretty major mods to need that gear. the biggest limiting factor is the intake that peaks around 4500 stock. assuming u buy a cam matched to the LTR TPI it will not need anymore then 3.45 either, basically because if its matched correctly the power will still not be high enough to need it. with the 3.73s and up the engine will run right out of its power curve. it might feel quicker but its not. the 3.45s in an auto are gonna drop gas mileage pretty noticably on the highway, and like mentioned earlier u wil loose top speed without upgrading the tranny. the comment about LT1s & LS1s have no bearing on this thread, LT1s and LS1s are different engines and require differnt parts to get the best performance out of it. apples to oranges.

 

IF the modified engine is capable of 5800/6000 rpm, 4.10s or 56s. I'm running 4.10s with a 700r4, 2600 rpm @ 70 mph.

 

How r u running that low. When I had my 700r4 before i switched to 5 speed Mine ran at 3400rpm at 75mph with 3.73's

With my manual, 2400-2500rpm with 3.73's Love every minute of it.

I think 3.73 is the best all around combination for mileage, which really doesn't matter if you are gonna be racing around anyway and performance. I have come to terms that to perform it takes fuel. lol

 

maybe he didn't change the speedo gears? I dunno..

I just went from 2.73's to 3.27's, and I don't think it's quite enough.. I think I'd be happy with 3.42 or 3.45.... but my car's still a daily driver..

 

I love my 3.45's

 

Old hot rod article said 3.55's were the best over all.


Matt

 

I run a 3.70 ratio 9-bolt behind my 6-speed and I couldn't be happier with the gearing. It's deep enough to really move off the line.....compliments the 2.66 1st gear of the T-56 very well. And with the .5:1 overdrive I can still catch good mileage on the highway (1700rpm@70 gets me about 23mpg out of a carbed 355.) If it's just an around-town weekend toy 4.10s would be fine, but they will shoot you right past the TPI powerband when you launch at the track.

The LT1 and LS1 cars like 4.10s because they're high-rpm powermakers (the LS1 especially.) TPI's strong point has always been low-rpm torque...take advantage of it.