Hi all! I am about to purchase a 8.5 inch 10 bolt posi rearend with 4.10 gears for my '68 Camaro. This rearend came from a early 70's Nova. If I wanted to change the gears to either a 3.73 or 3.55, do I have to change the carrier? I think the 4.10's will be too annoying for street use. Any help would be appreciated. Thanks.

Speedy68, I think you will be okay in changing to the 3.55 or 3.73 gears.For good reliable info team member "Big Gear Head" is your best choice.
This being your first post welcome to the site. :D

Gene is right, the 8.5 uses everything from the 2.73 to 5.57 on the 3 series differential. I don't know of any 3.55 that is available for the 8.5, but the 3.42 is very popular.

Thanks guys for your response, and yes, I am new to this great site. Big Gear Head, are you saying that this rear end has a 3 series carrier with the 4.10's? If so, I can change to a lower gear without changing the carrier. Also, will this rear end bolt in directly to my '68? Are the spring perches in the same location? Same width? Sorry for all the questions, but I want to find out all I can before I buy it. Thanks.

Check out The Nova Resource web site.... axle page:
http://www.novaresource.org/axle.htm

It should be a direct bolt-in for your Camaro. I've got a '73 Nova 8.5 just for the size increase in the diff. A lot of people upgrade their First Gens with bigger Nova rears.

Big Gear Head, one more question. What 3 series gear ratio's are available for this rearend? You mentioned in your response earlier that a 3.55 is not available. What is? Thanks in advance for your help.

HwyStarJoe, thanks for the link- that is exactly what I need to measure and check dimensions. You guys are the best!

Yes, you have a 3 series differential with the 4.10 gears. There is a 3.08, 3.23, 3.42 and 3.73 gear for the 8.5 rear end, and they will all bolt onto the differential that you have now.

Thanks big gear head! In your opinion, what gear ratio would be a better choice for the street- 3.42 or 3.73? I have a '68 Camaro Rally Sport that will eventually have a 400-425 horse small block, turbo 350 trans ( I do not have the torque converter yet, thats another question!), and the rear end we have discussed. The car will mostly be street driven with an occasional blast down the road or dragstrip. Thanks in advance for your help.

Thanks big gear head! In your opinion, what gear ratio would be a better choice for the street- 3.42 or 3.73? I have a '68 Camaro Rally Sport that will eventually have a 400-425 horse small block, turbo 350 trans ( I do not have the torque converter yet, thats another question!), and the rear end we have discussed. The car will mostly be street driven with an occasional blast down the road or dragstrip. Thanks in advance for your help.

I would probably go with the 3.42 for a car that will be driven mostly on the street without overdrive.

Thanks again big gear head for your help!