This will take you to the main site where there is history, technical information and other information on these cars.
This takes you back to the main page of the forums.
This is the control panel to change your password, information and preferences on this message board.
Click here if your lost your password or need to register on this message board. You must be a registered user to post. Registration is free.
Search this board for information you need.
Click here to buy cool Squarebirds mechandise.
Click here to support Squarebirds.org. For $20 annually receive 20mBytes webspace, a Squarebirds e-mail address and member's icon on the message board.
  #1  
Old 05-03-2017, 01:09 PM
RustyNCa RustyNCa is offline
Super-Experienced
 
Join Date: May 31 2007
Posts: 1,300
RustyNCa is on a distinguished road
Default 58 TBird 9" question

Just checking if anyone knows what the spline count would be on the rear end in my 58 TBird?

If anyone has a deal on different gearing and or a limited slip or locker I be happy to hear about it.

Cheers
Bryan

Reply With Quote
  #2  
Old 05-03-2017, 03:07 PM
Dakota Boy's Avatar
Dakota Boy Dakota Boy is offline
Super-Experienced
 
Join Date: Jun 30 2009
Posts: 1,498
Dakota Boy is on a distinguished road
Default

28 splines.

I have a 28" tall rear tire with 3.50 gears. C6 transmission. 70 mph is around 2800 rpm.
Reply With Quote
  #3  
Old 05-03-2017, 03:46 PM
RustyNCa RustyNCa is offline
Super-Experienced
 
Join Date: May 31 2007
Posts: 1,300
RustyNCa is on a distinguished road
Default

Quote:
Originally Posted by Dakota Boy View Post
28 splines.

I have a 28" tall rear tire with 3.50 gears. C6 transmission. 70 mph is around 2800 rpm.
See you are down the road I was thinking. 3.50 gears with a Trak-Lok and I have a C6 to install. Need to decide what stall I want in it. What are you running for stall?

What is your tire size? I am running 275x40x17s I think.
Reply With Quote
  #4  
Old 05-03-2017, 04:06 PM
simplyconnected's Avatar
simplyconnected simplyconnected is offline
Slow Typist
 
Join Date: May 26 2009
Posts: 7,080
simplyconnected is on a distinguished road
Default

Bryan, consider this...
A sun gear from an E40D fits nicely in a C-6. That swap lowers first gear by 20%, and it lowers second by about 15%. Third remains 1:1. It widens your ratios.

This is a great improvement off the line but doesn't affect highway driving so you get the best of both worlds. Another way to do this is by lowering your RE gears with an AOD. - Dave
__________________
My latest project:
CLICK HERE to see my custom hydraulic roller 390 FE build.

"We've got to pause and ask ourselves: How much clean air do we need?"
--Lee Iacocca
Reply With Quote
  #5  
Old 05-03-2017, 05:01 PM
RustyNCa RustyNCa is offline
Super-Experienced
 
Join Date: May 31 2007
Posts: 1,300
RustyNCa is on a distinguished road
Default

Quote:
Originally Posted by simplyconnected View Post
Bryan, consider this...
A sun gear from an E40D fits nicely in a C-6. That swap lowers first gear by 20%, and it lowers second by about 15%. Third remains 1:1. It widens your ratios.

This is a great improvement off the line but doesn't affect highway driving so you get the best of both worlds. Another way to do this is by lowering your RE gears with an AOD. - Dave
Interesting, I've never heard that. I would assume the 3.0 ratio is still very high tho.
Reply With Quote
  #6  
Old 05-03-2017, 05:17 PM
simplyconnected's Avatar
simplyconnected simplyconnected is offline
Slow Typist
 
Join Date: May 26 2009
Posts: 7,080
simplyconnected is on a distinguished road
Default

I guess the question is, do you want more torque at the rear wheels? Other than changing engines, the only way to get there is through your drivetrain's transmission, rear end gears and tire diameter. RE gears and tire heights are set in stone but transmissions offer a host of options.

I am a 'Ford guy' and have done this swap on my C-6. It works well and it's still a three-speed automatic. I'm passing this information to you. California should have many good transmission shops. They usually have a good supply of parts and the knowledge to assemble them. Get ahold of some old transmission shops and talk with the rebuilders.

Most Ford transmission changes were done in small steps because engineers were very mindful of 'backward compatibility' issues. A good, experienced Ford transmission guy will be familiar with the E4OD as it was an overdrive attempt OF a C-6. Many Ford transmission parts are identical from the Ford-O-Matic, all the way through. That means, rebuild kits often include the same parts that wear. - Dave
__________________
My latest project:
CLICK HERE to see my custom hydraulic roller 390 FE build.

"We've got to pause and ask ourselves: How much clean air do we need?"
--Lee Iacocca
Reply With Quote
  #7  
Old 05-03-2017, 05:37 PM
RustyNCa RustyNCa is offline
Super-Experienced
 
Join Date: May 31 2007
Posts: 1,300
RustyNCa is on a distinguished road
Default

Quote:
Originally Posted by simplyconnected View Post
I guess the question is, do you want more torque at the rear wheels? Other than changing engines, the only way to get there is through your drivetrain's transmission, rear end gears and tire diameter. RE gears and tire heights are set in stone but transmissions offer a host of options.

I am a 'Ford guy' and have done this swap on my C-6. It works well and it's still a three-speed automatic. I'm passing this information to you. California should have many good transmission shops. They usually have a good supply of parts and the knowledge to assemble them. Get ahold of some old transmission shops and talk with the rebuilders.

Most Ford transmission changes were done in small steps because engineers were very mindful of 'backward compatibility' issues. A good, experienced Ford transmission guy will be familiar with the E4OD as it was an overdrive attempt OF a C-6. Many Ford transmission parts are identical from the Ford-O-Matic, all the way through. That means, rebuild kits often include the same parts that wear. - Dave
Well, I am replacing the trans with a C6 for sure, I'm pretty sure the COM won't live long behind what I have done to the motor in the TBird. And it seems terrible form to have a car with a roots blown motor and not have a limited slip. So, changing the gearing also seems prudent.

But, I like the idea of having larger gear splits.

Thanks
Bryan
Reply With Quote
  #8  
Old 05-03-2017, 05:44 PM
Dakota Boy's Avatar
Dakota Boy Dakota Boy is offline
Super-Experienced
 
Join Date: Jun 30 2009
Posts: 1,498
Dakota Boy is on a distinguished road
Default

The stall on my converter is around 2600-2800. Tire size is 275/60-15.
Reply With Quote
  #9  
Old 05-04-2017, 12:47 AM
scumdog's Avatar
scumdog scumdog is offline
Super-Experienced
 
Join Date: May 12 2006
Posts: 1,339
scumdog is on a distinguished road
Default

Regarding those 'tall' gears as mentioned a couple of posts back:

I run a C-6 fitted with a shift kit but running a stock torque-converter behind the mild 429 in my '55 F100
I run an 'open' rear end with 4-spider 2.75 gears in my 9".

And the combo spins the 305/50/15" T/A's easily - at times too easily...

So if your motor has torque and you're not after the ultimate 1/4 mile time 2.75 gears will be OK.

(Stock gearing in the C-6 gives me just over 100mph in 2nd gear.)
__________________
A Thunderbirder from the Land of the Long White Cloud.
Reply With Quote
  #10  
Old 05-04-2017, 01:27 AM
simplyconnected's Avatar
simplyconnected simplyconnected is offline
Slow Typist
 
Join Date: May 26 2009
Posts: 7,080
simplyconnected is on a distinguished road
Default

Tom, by 'open' do you mean you have non-limited slip (non-positraction)? And by 'four spider gears', are two splined for your axles and two are on the carrier pin? I guess I'm asking if this is a regular conventional setup or something that is custom.

The only reason we use low ratios (like 3.9:1 or 4.30:1) is for launches. Tall gears (like 2.75) tend to come apart when 400-500 HP tries to spin slicks off the line. I've seen axles twisted a half-turn as a result as well.

A 4.30 ratio will easily transfer 500 HP because more ring and pinion gear teeth are engaged at once and torque is doubled over a 2.75 just because of the ratio. I've seen 'tall' gears explode upon launch.

Bonneville cars use tall gears because they are looking for 'maximum top end speed' regardless of how long it takes to get there.

I don't know why but Ford puts tall gears in convertibles. When my Mustang was stock, the 5.0/AOD got me to 150 MPH but it took a very long time to get there and there was more elbow room left on the tach. The engine simply didn't have any more to give. Not bad for 'stock' but I wasn't satisfied with acceleration so I built a 351W. - Dave
__________________
My latest project:
CLICK HERE to see my custom hydraulic roller 390 FE build.

"We've got to pause and ask ourselves: How much clean air do we need?"
--Lee Iacocca
Reply With Quote
Reply


Thread Tools
Display Modes

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 08:35 PM.

Driving, racing or working on cars can be hazardous. The procedures and advice on this website including the message board are opinion only. Squarebirds.org and its webmasters and contributors do not guarantee the correctness of the advice and procedures. The Squarebirds.org and its webmasters assume no liability for any damage, fines, punishment, injury or death resulting from following these procedures or advice. If you do not have the skills or tools to repair your car, please consult a professional. By using this site you agree to hold harmless the Squarebirds.org, its authors and its webmasters from any resulting claim and costs that may occur from using the information found on this site.

Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Any submissions to this site and any post on this site becomes property of Squarebirds.org . The webmasters reserve the right to edit and modify any submissions to this site. All material on this is site is copyrighted by the Squarebirds.org. Reproduction by any means other than for personal use is strictly prohibited. Permission to use material on this site can be obtained by contacting the webmasters. Copyright 2002-2016 by Squarebirds.org.