2.57 to 3.08 rear end gear caprice - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Transmission - Rearend
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-17-2013, 05:33 AM
Registered User
 
Join Date: Nov 2013
Posts: 4
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
2.57 to 3.08 rear end gear caprice

I have a 1980 chevrolet caprice saloon 305 and TH 350

I bougt some uppgrades for more touque (i hope)

The engine is going to have an elgin 923 cam and edelbrock performe 2101 intake and single 2,5" exhaust with open mufflers and 4bb rodchester.

The question is that i think i have a 2.57 gearing and a friend of mine have a 3.08 he dont use, and i am wondering if this is going to be better.?

High rpm cruice issues?

Fuel economy is not an issue...

Sorry about bad english

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-17-2013, 07:19 AM
delawarebill's Avatar
Registered User
 
Last photo:
Join Date: Mar 2009
Location: delaware
Posts: 1,253
Wiki Edits: 0

Thanks: 16
Thanked 64 Times in 64 Posts
gears

i don't think moving up that much is an issue.. but go to summit and look up "ring and pinion gears' just below any gearing there is a calculator. now u've got the measure the OD of the tires for this. click on what answer u want and fill in the other 3 blanks and hit cal.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-17-2013, 07:45 AM
Registered User
 
Join Date: Nov 2013
Posts: 4
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by delawarebill View Post
i don't think moving up that much is an issue.. but go to summit and look up "ring and pinion gears' just below any gearing there is a calculator. now u've got the measure the OD of the tires for this. click on what answer u want and fill in the other 3 blanks and hit cal.
Thanks... i saw about 350 rpm higher at 55mph
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-17-2013, 08:09 AM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,046
Wiki Edits: 0

Thanks: 10
Thanked 412 Times in 355 Posts
The 3.08 will still be fine on the highway. You will notice a little better performance from the change. I'm assuming that you are talking about changing the whole rear end. There is a lot involved in change the gears, but not in just swapping a complete rear end.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-17-2013, 08:29 AM
Registered User
 
Join Date: Nov 2012
Location: Atlantilc iowa
Posts: 423
Wiki Edits: 0

Thanks: 0
Thanked 26 Times in 26 Posts
If you change the gears, I'd recommend you get the kit with the new bearings, seals and ect. . Get someone who knows how to do it. Its not just changing parts.
there is no problem in using, used parts if they're good ones. Just don't go cheep without replacing bearings and such, because i'm guessing there is a lot of miles on that chevy.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 11-17-2013, 10:20 AM
Registered User
 
Join Date: Nov 2013
Posts: 4
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks alot for the info.

i have help from a spesialist and im going to bye a bearing kit
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 11-17-2013, 12:01 PM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,046
Wiki Edits: 0

Thanks: 10
Thanked 412 Times in 355 Posts
Setting the pinion depth on used gears is very tricky. The contact pattern is very hard or impossible to read.

This question hans.t been asked yet, but are the gears from the same rear end as what you have in your car? If you have the 8.5 10 bolt then you must use gears from a 8.5 10 bolt. Also, your 2.56 gears will be on a 2 series differential. If you have the 8.5 then you will have to get a 3 series differential for the 3.08 gears to fit. If you have the 7.5 rear end then the 2.56 and 3.08 gears both use the 2 series differential. Like I said before, there is a lot to a gear swap.

Be sure to get a high quality installation kit. The cheaper kits like Ratech are junk. I don't know where you are, but getting a good kit might be a little more difficult if you are not in the US.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 11-17-2013, 01:45 PM
Registered User
 
Join Date: Nov 2013
Posts: 4
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have a the original rear axle on the car (caprice 1980) and from what i have learned it is a 8.5 10 bolt.

The 3.08 parts are from a 1970-80 gm axle also a 8.5 10 bolt

I have only done this once before in my chevrolet camao, when i changed from 3.08 to 3.73 this was a 7.5 (richmond gear) 10 bolt axle from a 1996 camro that i used in a 1987 camaro
Then i was running a 700R4 trans so the rpm on the highway was ok...but this time i have the TH350 so i dont want to go as far as 3.73

I am from Norway and the are som good companies here thas spesialises in american car parts, i also shop from Jegs and Summitracing



Thanks again for helpful information
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 11-17-2013, 01:51 PM
big gear head's Avatar
High Performance Rear Ends
 
Last photo:
Join Date: Nov 2009
Location: Central City, KY
Posts: 2,046
Wiki Edits: 0

Thanks: 10
Thanked 412 Times in 355 Posts
So with the 8.5 rear end you will be needing a 3 series differential to go with those gears.

Summit and Jeg's installation kits are not very good, not any of them. If you can get a Yukon kit from someone local it will be a much better kit.
Reply With Quote Quick reply to this message

Recent Transmission - Rearend posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
1987 Caprice rear end 87box Transmission - Rearend 8 11-15-2012 08:50 PM
1990 caprice with rear end upgrade questions cudablack2004 Transmission - Rearend 2 11-14-2011 07:13 PM
87 caprice Rear end swap with later unit? erbysandman1 Transmission - Rearend 1 04-06-2008 11:48 AM
95 caprice rear end swap? molotov 350 Transmission - Rearend 2 04-08-2007 02:04 AM
'91 Caprice 9C1 rear end noise Sandflea427SS Transmission - Rearend 3 02-21-2007 05:55 PM


All times are GMT -6. The time now is 07:12 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.