I have a 10 bolt, 2.73 gear open diff from the factory on a 67 Camaro. Need to switch to 3.55 or 3.73 gears, and I believe I need a new carrier, or at least suspect I do. THe gear shop said I could only go up to a 2.97 or perhaps 3.08 with existing carrier before using a spacer...

Two questions, and pls only reply if you are certain:

1. Do I need a new carrier for this gear swap... 2.73 to 3.73?

2. Is a spacer safe and dependable to use?

Thanks

Check on the availability of a gear set with a thicker ring gear, which does away with the need for a spacer. BGH should have the correct info....

You are correct, you need a new differential, or carrier. The 2.73 gear goes on the 2 series differential and you will need a 3 series differential for the 3.55 gears. This would be a very good time to install a new 3 series Eaton posi. I don't recommend using a spacer, although many people have successfully used them.

Thanks big gear head... yesterday I had two "qualified" mechs tell me it required no mods... just install. But in the back of my mind I remember reading a tech article that discussed this, and when you mentioned, "series" in your post, that brought it back. Plus, a gent working at Autozone who has three first gen camaros said you could just swap it out. Amazing the amount of misinfo out there. As I remember, you could bring a 2.73 to a 3.08 at the most, above that required new carrier.

Thanks again

That is a pretty basic thing that the gear shop should have known. I think that is pretty scary if they didnt know that. It would make me think twice about using them. :eek:

LOL... so I called the shop back I had planned on using, and told him what you had posted GearHead... and he says, "Yea, that might be right. I don't do many rear ends anymore, all the work is front wheel drive." I thanked him for his help anyway, no sense being mean about it, but yes, I did have reservations, and in my continuing rear end saga, just kept investigating. Ha.

With the 8.2 10 bolt and the 12 bolt, even a switch to the 3.08 would require a 3 series differential. The 8.5 10 bolt is a different story. This one uses a 3 series for the 2.73 gears, so you can install anything up to a 5.56 on the same differential. The 7.5 10 bolt uses a 2 series for the 2.73 and 3.08, so you would only need a 3 series if you went to a 3.23 gear or beyond. I don't know why they had to make it so complicated. I hate to brag on Ford on a Camaro sight, but Ford only made one differential for all of their gear ratios.

GearHead,
How far out from Cinci are you... I might pay you a visit in the Camaro on a nice day... buy some lube...

smile.gif

Also, I've decided to just give up and bite the bullet. I'm going to a COMPLETE set up using a 12 bolt. Tomorrow I'm having a set of five leaf springs put in place of the mono's, so at least I'll have fresh hardware back there to drop out when I find one. I do most of my work, but this IS a good shop, and for $180, I'll let them fight almost four decades of grime and rust.

HEY!!! I JUST found a 12 bolt Gear Head... this looks like it would bolt right up with the new springs/perches back there... do you concur?

http://www.camaros.net/cgi-bin/cyber/classifieds.cgi?search_and_display_db_button=on&db_id=27587&exact_match=on&photo_size=full

Plus, he is close...

That's not a 12 bolt, it's an 8.5 10 bolt. It is a good rear end and stronger than the 8.2 10 bolt that is probabl in your car now. I can fix you up with a new 12 bolt if you are interested, but it isn't cheap. I think I'm about 6 hours from Cinci.

Fred u've got mail...

jethro, something is wrong with my email today, I only got 19 spams (usualy about 115). I didn't get your email. Please try again.