This is a good question because i've been thinking about changing the gear in mine, so I'll see what you think and give you as much info as possible, My car is a daily driver and i more then occasionally get on the highway and run it up over 130 but i was thinking since most of the time it seems to be just a red light racer that a little more low end might be nice without dropping a lot of money in the engine, I have a lt1 its a jasper crate but its built to stock spec, 100 shot n20, cold air intake and that's about it, I just had my trans rebuilt (4l60E) with a trans-go kit, corvette servo, upgraded converter etc, I don't plan on doing much to the engine but i do plan on in the near future to upgrade the map (granatelli for cold air) digital 6 so i can can a perf tune and ret for the n20. Im running 18" rims all the way around but i used a tire calc and got the tires sizes so the overall tire dia is very very close to stock. I plan on upping the shot to 125 also. I guess thats all I can think of.
Thanks.

 

What gears do you have now?

If you have 3.23s then look for some 3.73s.
If you have 2.73s then look for an M6 3.42 rearend. (cheaper/easier)

 

I'm running 3:73s on my LT1 4L60, and they're a nice compromise. Good acceleration, and still livable at freeway speeds

 

Cool thanks. I'm not sure what is there now, I know its still factory. My guess (judging by crappy 1/4 times) that its the 2.73's. Guess i need to find that out.

 

Well i found the gu2 code so now i know that its got the 2.73, now i need to figure out whether i have the 7.5 or 8.5 rear. then my next question is, summit has one that says this, "Pinion gear will not accept the factory anti-lock reluctor." Is that just specific for there part? If I buy a used one will I have this problem, and is a gear that is made lighter as I have read some performance ones are, going to make that much difference on a daily driver.?

Thanks

 

You have a 7.5
I have not seen or heard the "will not accept factory anti-lock reluctor". If you want to go cheap, get a set of 3.73's out of an S10 at the junkyard (4.10 are also available). Plus there is always e-bay - but you don't know what you are getting.
Use the factory shims in both the pinion and sides and you should be very close to perfect. Double check with gear marking compound and run a backlash check.
Finally, save your time and money, just get the 3.73's for a surface street mainly car or 4.10's for a drag only car. Skip the 3.42's. I have 2 rear-ends, 1 w/ 3.73 and 1 w/ 3.42 The 3.42 does not seem to save anything on gas and really only hurts the acceleration. Also, the posi carriers are weak. I have gone through 3 of them until I got one of the ratchet type out of a blazer - I have not been able to burn the clutches out of it.
Just my $0.02

 

my only concern is long runs on the highway....a few months ago i did a run from tampa to orlando with some guys and we were 100 or better most of the way, so will that be a problem with 3.73's? I don't care about saving gas

thanks for your .02

 

The 3.73's will go 100mph no problem, its if your engine can stand it is what matters.
According to this calculator http://www.f-body.org/gears/ you will be at 3400 rpms in 4th gear at 101mph. Asuming the tire size is correct, you can check it yourself for complete accuracy if you would like. Since I do not know your exact tire size, it might be best for you to check it.

 

I looked at a different calculator because that website you posted was set as potentially dangerous for spywhere by google? anyway, even though my tires and rims aren't stock, I still came up with pretty much the same numbers. 85-100 was 2900-3400 rpm, so I drove home today in second gear running it steady at those rpm's, and I have to say I'm glad I only live 10 minutes from work, those type of rpm's for an hour drive seems pretty harsh. Changing gears sure is a quick and easy way to drop you 1/4 times but I'm not sure if its worth the highway sacrifice. I almost bought new gears on ebay yesterday till I read your post about the rpm calculator. thanks for that. Now I think I'm going to have to think about it a while. Maybe I just need to explorer other options to get more hp.

Thanks for everyone's input.