rear end gear swap
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
It's all a trade off. My Camero has a 2.73 and a 4 speed. It's great once you get going in first gear. The real cure for 3.08 is one, more power or two, more gears like a 5 speed
Last edited by gkull; Sep 24, 2010 at 01:36 PM.
Instructor
Joined: Sep 2009
Posts: 190
Likes: 0
From: Hiawatha Iowa
There was a guy on this forum named Gary but was forced to another forum: Digital Corvette because besides offering excellent advice he also sales his services for rebuilding differentials and trailing arms.
I'm in the middle of a differential rebuild and will be changing the 3.08 to a different gear ratio too. With your approval because I don't want to hijack your post maybe we can post pictures of our progress together on this post and see what advice we get and lessons learned for each other. I've heard Toms sales very goog ring and pinion parts for differentials the are USA made and not that cheap China made junk.
I'm in the middle of a differential rebuild and will be changing the 3.08 to a different gear ratio too. With your approval because I don't want to hijack your post maybe we can post pictures of our progress together on this post and see what advice we get and lessons learned for each other. I've heard Toms sales very goog ring and pinion parts for differentials the are USA made and not that cheap China made junk.
Thread Starter
Instructor
Joined: Jun 2008
Posts: 100
Likes: 1
Any actual work will be a month or two away. I was hoping to purchase parts now and do the work in the winter. I assumed this was a common swap/replacement for many owners. I have done a few engine mods and feel the gears would enhance that.
Burning Brakes
Joined: Sep 2008
Posts: 805
Likes: 5
From: Naperville Illinois
Did the swap a year and a half ago on my '68. Went from the stock 3.08 to 3.73's from Tom's Differentials. Did all the work myself with advice and and extensive use of the posts from the aforementioned Gary Ramadei. Search this forum and the other as well as Google.
I highly recommend the US Gears 3.73 R&P from Tom's. I ordered a cheaper set first, and didn't like the looks of them when they arrived, so I got the Tom's and was very glad I did. They were obviously better quality (made in Chicago!), easy to pattern and are SILENT. Now my tired old (original) 327 with a THM 400 spins 'em good out of the hole, and chirps on the 1-2 shift. Some guys will tell you to get the 3.55's because of highway RPMs, I honestly don't think it's a problem. Fuel consumption is another matter...
Cheers and good luck!
I highly recommend the US Gears 3.73 R&P from Tom's. I ordered a cheaper set first, and didn't like the looks of them when they arrived, so I got the Tom's and was very glad I did. They were obviously better quality (made in Chicago!), easy to pattern and are SILENT. Now my tired old (original) 327 with a THM 400 spins 'em good out of the hole, and chirps on the 1-2 shift. Some guys will tell you to get the 3.55's because of highway RPMs, I honestly don't think it's a problem. Fuel consumption is another matter...
Cheers and good luck!
Drifting
Joined: Apr 2008
Posts: 1,305
Likes: 2
From: Lewisburg WV
thegazman
One thing you must consider is what you use your car for. My 79 came with a factory 3:73. It's great around town, but I hate going on a trip in it as on the interstate I am tacking 3500 rpm's The gas mileage is terrible and it's noisy due to the high rpm's.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Having had several FDR's in C3's over the years, I've been very satisfied with the 3.55 which I went back to in my NOM BB/manual '78, but if you're open to other options than changing your rear gears I tend to agree with gkull that more power and/or a 5 speed would likely also get the job done. Feel free to PM me if you need Gary R's contact info.
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Instructor
Joined: Sep 2010
Posts: 236
Likes: 0
gear discussion
I have 3.08 gears in my '78 SA. When I start out I always feel like I'm starting in 2nd. So is there an alternative to sacrificing starting issues with highway cruising issues? What would be the 70 mph rpm of 3.55 gears? Thanks in advance.....
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
No disagreement it is simple math. You can use this one from Keisler or go online and find a bunch of them.
http://www.keislerauto.com/speed_analyzers.php?sa=gm_5
http://www.keislerauto.com/speed_analyzers.php?sa=gm_5
Last edited by Gordonm; Oct 2, 2010 at 01:24 PM.
Intermediate
Joined: Sep 2010
Posts: 27
Likes: 2
rear end gears
No disagreement it is simple math. You can use this one from Keisler or go online and find a bunch of them.
http://www.keislerauto.com/speed_analyzers.php?sa=gm_5
http://www.keislerauto.com/speed_analyzers.php?sa=gm_5
Thanks
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Here is a different one.
http://www.rearendparts.com/pages.php?pageid=16
Another one
http://www.race-cars.net/calculators...alculator.html
Last edited by Gordonm; Oct 2, 2010 at 02:15 PM.
Intermediate
Joined: Sep 2010
Posts: 27
Likes: 2
Burning Brakes
Joined: Jan 2006
Posts: 957
Likes: 6
From: Burlington wisconsin
I am very happy with the 3:55's
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
