Need help to confirm dimensions 71 rearend size

[dave@ztech]

Hi Everyone,
So I am going to purchase a floater rear that is based on a ford 9" rear in that it uses a 9
ford center section , I am buying from Speedway Engineering , and he wants to confirm the size and where the spring perches will go , so I found this info here
The following dimensions are consistant across all 3 style rear ends.
- Axle tube flange to axle tube flange: 55.25"
- Between centerlines of spring seats: 45 3/8"
- Axle shaft length: 30 5/32"
the Axle length is not important , however, I just need to be sure he has the right numbers, also, I think I really also need to know the finished size, the size from side to side, where the tires bolt on, is that the 62.5 that I see also ? Is that the Flange to flange size? On a side note, just to confuse me more a friend said, make sure the center is the correct offset?? I thought it was in the center? Right? Anyways need the wisdom of the site, and also if there is something else that I should be sure that they know so that what I recieve after Weller racing puts the brakes and lines and center section in , it will be bolt in ready , HAA HA
Thanks

 

[badazz81z28]

Yes, it’s going to be offset. When DSE built my housing it was 1/2”. I’ll see if I can dig up the invoice. I’m surprised they don’t have those specs. Surely they have built a rear for a sec gen.

 

[dave@ztech]

They have , however, they want the client to provide the numbers, I am sure it's to cover there butt, so if it's wrong size not their fault, HAA HA

 

[G72Zed]

Sounds like your friend is referring to the difference in pinion offset from the GM 10/12 bolt of 1/2 inch vs the Fords 9” 15/16 offset.
Measure up carefully, and line things up to limit the driveshaft working angles. Our cars are also known to have the rear end offset to the passenger side adding to the compound working angles. Now is the time to get it right.

 

[dave@ztech]

I am ordering the rear rims with the following 18x9.5 5.5 BS , and the center section will have 31 splines and it has some sort of finishing to reduce , the drag? that is inherent in the 9 inch, I will post more information on this, as I receive the information
Thanks

 

[badazz81z28]

You probably mean REM finish. If your getting a new 3rd member highly consider US Gears new “Stealth Gear” is supposed to be quite!

 

[big gear head]

The pinion is offset 1/2 inch to the right from center, which makes the right axle tube 1 inch shorter than the left. The total width from axle flange to axle flange is 61 inches. I don't know who came up with that 62 1/2 inch measurement but it's all over the web and it's WRONG. I think the spring perches are 45 1/4 center to center. When I was building rear ends every day I had all of these measurements fresh in my mind, but it's been a few years since I built one, so I'm not 100% sure. If you have the rear end in your car then measure it yourself so that you know what you have.

 

[G72Zed]

I am ordering the rear rims with the following 18x9.5 5.5 BS , and the center section will have 31 splines and it has some sort of finishing to reduce , the drag? that is inherent in the 9 inch, I will post more information on this, as I receive the information
Thanks

Did you ever consider in using a GM 12 bolt with Big Ford ends instead of the 9" ?, would not have to screw around with the offset.

 

[dave@ztech]

I did, however, I am liking the floater rear from speedway engineering, and the price

 

[badazz81z28]

I don’t see any value using a 12 bolt unless you want to keep a car “GM”.

when I had an issue with my 9”, it was so nice to be able to pull a 3rd member like nothing.