I was wondering if anyone uses anything above 4:10's.My dad has 4:56's on his olds 442.He says 4:10's would be great for my car but I was wondering how my car would do on the highway and street since we have double overdrive trannys.In 4th gear on his car at 50mph he is around 3000 rpm.

 

if you drive it often on the street... don't go below 4:10's....

 

A friend of mine just went from 4.10s to 4.56s but he also went from a 26" tire to a 28" tire at the same time. He said on the hiway there is less than 100rpm difference between the two.
I think 4.56 is too much for street tires but if you run at least ET Streets then you will like it a whole lot more.

If you still can't decide you can always go with a 4.30 gear.

 

i dont think its has anything to do with the tires besides the fact that youll be shreadin em at each light, but the car will suck on the freeway, and youll have run in the higher gears just to keep up with the flow of traffic and keep the rpms down. definatley dont go with 4.56s unless your car is drag only!

 

Tire height makes a difference.I'd stick with no more than 4.10s'

 

MY buddy has 4.56`s in his LS1 and he can`t launch is worth a crap. I`d imagine an Lt1 would be no different.

 

Im running them and i totaly loving them there is two different cars between the 4.10's and the 4.56's the 4.56 is faster. It dont jus feel faster it really is i kno by racing. Id only run them if u can turn 6500 or so. It made my car unbelievable. With my nittos and the stock setup i could take off and it just squeak them but the new set up its spins prolly 5 foot them im gone. you will like them i promise. I hope you kno a good rearend guy tho because u have to cut the cross pin. thats my opion. All these guys say no with out trying the gear, im running it.

 

Im running 4.33 gears, my buddy is running 4.56, both lt1 6 speeds. I have cut many upper 1.7's 60' on ET streets, he just went 1.66 2 nights ago with the 4.56. Both are cars are street driven all the time.

I would only suggest this route if you have a cam however. Shifts seem to keep you above 5k rpm ALL the time. This isnt the area a stock cam likes to shine. However it puts me right in the fat part of my powerband, and it does my friend.

Highway cruising does go up a bit in RPM, but i really didnt lose much in gas milage. City driving you just shift more, and the ability to use 6th on the street is really nice.

I would NEVER go with another gear in mine.

 

Your before and after shift rpms are completely determined by the tranny independent of your rear end gear.

I use 6th all the time starting at 40 mph and i have 3.73s

When this car becomes a toy i'm definitly going to gear it down more. My car doesn't like being powershifted into 5th though so i'd need that rebuilt.

Do you hit 5th at the track, or do you wind your motor really high?

I say go for anything other than 4.10s, higher or lower, doesn't matter. As long as you don't conform to the masses

 

Yes you are right, let me re-phrase that. Even while the shifts will drop the rpms the same amount with different rear gears. ie 1-2 shift will drop you ~2k rpm no matter the gear, with a larger gear, you will be able to spend more time in your peak powerband with a bigger cam, while with a stock cam, you will spend less time in peak power.

I cross in 4th, about 6300rpm, which is actually a tad below my shift points.

As for using 6th at 40mph with 373s, lets just say my car idles at a higher RPM than what that is pulling right there