66 impala rear end - Impala Tech
Performance Our High Performance Area

 
LinkBack Thread Tools
post #1 of 2 (permalink) Old 08-05-2010, 03:21 AM Thread Starter
 
 
Join Date: Aug 2010
Location: canada bc
Posts: 5
 
Smile 66 impala rear end

hi im new to the site my toy is a 66 impala. im having a motor build with about 370 hrse and got a 700r4 trans. currently i have the stock 10 bolt. has anybody had any problems with these rearends breaking if upgraded to posi and or bigger gears? i probly got 273 or 308s and i know its open. should i just upgrade to the 8.5 10 or 12 bolt? im looking for cheap without welding of course. im probly thinkin 355 or 373 gears. any help, experience or if any one has a 12 bolt it would b much apreciated.
mean66 is offline  
Sponsored Links
Advertisement
 
post #2 of 2 (permalink) Old 08-05-2010, 02:00 PM
Moderator
 
Join Date: Jan 2006
Posts: 10,627
 
Welcome to the Team Don!

You are still within the power range of the ten bolt rear end. You are bumping up against the upper limit at 350 horsepower; but with street tires, you should still be safe. A PosiTrac rear end from Eaton will not only make your driving experience more enjoyable but a little safer and help the rear end to last longer.

As one tire spins, the gears inside turn at twice the tire speed. They are riding on a bronze bushing without the benefit of force fed lubrication. So the side and spider gears will weld themselves to the differential case if you do it often enough, or long enough, resulting in the rear end breaking.

The weakest part of the 1966 ten bolt rear end was the axels so an upgrade to aftermarket axels and all new bearings and seals would be a good thing. For the amount of money you will pay for a new Eaton PosiTrac differential, a new gear set, new bearings and seals and shims to set up the rear end (not normally found in a rebuild kit) plus the price of new axels you are close to the price of a store bought 12 bolt rear end from the aftermarket (Moser, or Currie for example). I would compare the total costs of a new 12 bolt (that can handle nearly twice the power of a ten bolt with the right parts in it) compared to rebuilding your old ten bolt.

Don't forget to include labor as it is not a bolt in experience to set up a rear end with new gears (it can be done but if you get the set-up wrong you can destroy a set of gears in ten minutes driving time). If you stay with your original gear set you just reuse the shim packs you have now and replacing the bearings isn't that difficult (though it will require a hydraulic press for the pinion bearing and a strong arm to crush the new crush sleeve).

Big Dave
Big Dave is offline  
Sponsored Links
Advertisement
 
Reply

Tags
12 bolt, gears, posi trac, rearend

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Impala Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
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:
OR

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.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



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

 
For the best viewing experience please update your browser to Google Chrome