what normally is the ratio for a lt4 ? My car is turning about 1700 at 75 mph in 6th gear, what would that be? Or how do I tell what the gear is? How much higher would the rpms at 75 mph with the 4.10 gear?
Now for the important part, what does it cost to change out the rear gears?

How much difference is there between the blue and white striped Grand Sport and the ones with just the lt4 and 6spd? My lt4 doesn't have the ride control **** or sport seats, is it pretty much the same as the GS models ?

 

All `96 6-speeds have a 3.45 rear axle from the factory.
There is no difference in the engine, (LT4) tranny or rear axle, between the `96 LT4s and the Grand Sports.

 

Stock gears for a 6-speed is RPO GM3 which is 3.45 ratio. Look in your center glove box under the carpet for the RPO sticker, bunch of 3-4 didgit codes. Find out what options you have from the codes here: http://www.corvetteactioncenter.com/...o/8496rpo.html

GS option gave you 315 rear tires, 5 spoke blk wheels and special paint scheme and special seriel number sequence. Thats about the only difference.

 

I was recently quoted ~600 to do a gear swap to 4.10s (including the parts) by a differential specialist. I have been quoted alot more in the past by non-specialists... The one thing you have to consider for changing gears is that, after the swap, your speedometer will not read the correct values. There are essentially two or three ways to correct that (that I'm aware of):

1) Physically change the speedo gear (in the tranny, maybe?) to correct for the new rear-end,
2) Purchase a Hypertech Power Programmer III and simply reprogram the computer,
3) Send your entire ECU out for reprogramming.

Any of the above methods will work - it's just a matter of $$$ for labor, $$$ for the Hypertech, or time away from your car (since the ECU will be out and away) as well as money to reprogram it. I would be willing to guess that 95% of the people here who've done gears have gone the Hypertech route. New, they're in the $300-400 range, depending on where you purchase it. However, they can be readily found used on eBay for much less (about half)...you just have to make sure you're getting the correct unit for a 96 LT4 vette.

Hope this helped at least a little!

EDIT: BTW, it might help you to include in your profile where you're located (city, state). There very well could be members locally who've done the mods you're interested in, or who can recommend a reputable shop that you might not otherwise find by flipping through the yellowpages.

 

With 4.10 gears you will turn 2000rpm and about 73mph.
Very streetable..you might loose 2-3mpg on the highway

$600 sounds too low for complete change out IMHO....maybe from a good backyard mechanic.....

I used Dana 4.10 gears

 

Local shops here have quoted $1000-1300 for the job. For $600 sounds like you'll have to pull your own rear end and take it to this specialist. It's an easy way to save some money if you can pull it out yourself. However, if this includes them removing it out of the car then I would be leary of such a low price.

 

If I had it to all do over again, 4.10's would be my first mod.

I paid $300 for the 4.10 gearset, and $350 for the turn-key install.

 

=$650

I said the quoted me ~600. I would expect 650 is in the ballpark... A local ZR-1 member had them do a set of 4.09s in his car for 500 - no mention of pulling the diff himself.

 

Again, you guys are amazing!
Thanks!!