Impala - Impala Tech
Welcome Forum New to the site? Introduce yourself.

  • 1 Post By 67SS
LinkBack Thread Tools
post #1 of 5 (permalink) Old 10-16-2019, 09:12 PM Thread Starter
Join Date: Oct 2019
Posts: 1

Hey everyone im new to this i have a question i have 64 impala i wanted to put in a posi my engine is 283 v8 can i put a 5.38posi
Luis Perez is offline  
Sponsored Links
post #2 of 5 (permalink) Old 10-16-2019, 10:36 PM
Join Date: Jan 2006
Posts: 12,528

Highest ratio from the factory was a 4.10

Highest from the aftermarket was a 4.56

Posi yes, but I wouldn't put any money in that rear end.

When I was younger they were plentiful and cheap so I could blow up one a week and rebuild another out of the junkyard. I can not recommend that attitude today as they are not plentiful though they are still weak, and subject to failure if abused. Even a 283 can break one if you side stepped the clutch above eight grand. Only justification for a 283 is to shift it at ten grand like I used to. But then again 283's were plentiful back then too, and they used to fail at that RPM frequently.

Big Dave
Big Dave is offline  
post #3 of 5 (permalink) Old 10-18-2019, 03:08 PM
Senior Member
Join Date: Jun 2014
Location: San Jose, CA
Posts: 296
Welcome to the team. Why would you need 5.38 posi? Is this a typo??
What are you planning on doing with the car and what transmission do you have?
BA. likes this.
67SS is offline  
post #4 of 5 (permalink) Old 10-18-2019, 04:20 PM
Join Date: Jan 2006
Posts: 12,528
5.38 is a common twelve bolt gear for a SBC or a light truck towing a heavy trailer.

The rear end in a '64 was designed in 1944 for a 216 cube six cylinder. It was rated for 150% of the torque output of that particular engine (193 x 1.5 equals 289.5 foot pounds of torque max!). Most SBC exceed this amount of torque so the only reason it lives at all is because the tires slip. If they don't; you have a broken rear end. All of the other GM cars had a V8 long before Chevrolet did so they had a stronger Pontiac-Olds style rear that had a massive ring gear and huge axles that puts a Ford nine inch to shame. I looks like the Chevy rear only bigger.

Because of the eight inch recapped cheater slicks I ran on my '53 Chevy with a 409 power plant I broke my rear end so often I kept another "P" case pumpkin with 4.10 gears ready to bolt in in the side of the road in my trunk.

Big Dave
Big Dave is offline  
post #5 of 5 (permalink) Old 10-22-2019, 01:10 AM
Join Date: Aug 2008
Location: Miamisburg, Oh.
Posts: 3,176
Blog Entries: 15
Agree with 67SS that using a 5.38 in a stock 10 bolt is a No-Go. Even in a built 10-bolt, the car it self would become a PURE drag-only kind of car.........and probably even IF it had tall tires on it to reduce effective gear ratio.

Short answer - from what you've told us - it can be done but is a bad plan.

BA. is offline  
Sponsored Links

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


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