Which differential for a scratchbuild?

[eschaider]

The Dana 44's are very nice units and have served well for several decades, increasing power levels not withstanding. There is a relatively good supply of aftermarket parts available for them and by and large I have not heard of people who had any significant design, fabrication or installation issues with them. If I were going to use one I would definitely use one of the Kirkham units, that are easily the very best and nicest Dana 44's available anywhere today.

The other very good choice as several have already said is the 8.8 inch Ford IRS center section as used in several of their passenger cars. I would recommend you look for an 8.8 IRS housing out of an Explorer rather than a passenger car. The Explorer 8.8 IRS housings are by far the most robust of all the aluminum 8.8 IRS housings Ford has ever produced. Be sure you get a 2007 through 2010 housing. Those are the ones with the massive front ears for locating the nose of the housing.

When ACE23 was struggling with the same decision alternatives you currently are I posted up some pics and suggestions for him on the site here. This is a link to the post => Ford 8.8 IRS Suggestions.

You might find something in there that could be helpful as you go about noodling out the best alternatives for your build.

BTW congrats on the decision to do a scratch build. It is the best way to get your Cobra exactly they way you always wanted and thought they should be — lots of work but also lots of satisfaction and immense pride in the finished product that is YOUR Cobra.


Ed

[120mm]

Originally Posted by Three Peaks

I installed an 8.8 Tbird IRS in and original style frame. It was a bit of work, but it fit and was affordable and I was able to adapt the Ford uprights with my scratch built control arms to make it all work. Let me know if you need any pictures and I'll see what I can do. Much cheaper than the Jag IRS pumpkin and a much, much less than the Kirkham offerings and original style uprights.
If you are building a 289 leaf spring chassis and original uprights, this can also be adapted to that unit easily.

Bob

That is good to know. My wife and I are adding up the costs of this build and would like a more affordable option.

I would very much like pictures of your setup. It will help with the decision, for sure.

Originally Posted by Tom Kirkham

The pictured Jag diff top adapter mount in post #13 will not work in an original specification 289 leaf spring chassis, it is too tall and will hit the frame. However, that adapter mount will work in an original specification 427 coil spring chassis.

Also very good to know.

Originally Posted by eschaider

The Dana 44's are very nice units and have served well for several decades, increasing power levels not withstanding. There is a relatively good supply of aftermarket parts available for them and by and large I have not heard of people who had any significant design, fabrication or installation issues with them. If I were going to use one I would definitely use one of the Kirkham units, that are easily the very best and nicest Dana 44's available anywhere today.

The other very good choice as several have already said is the 8.8 inch Ford IRS center section as used in several of their passenger cars. I would recommend you look for an 8.8 IRS housing out of an Explorer rather than a passenger car. The Explorer 8.8 IRS housings are by far the most robust of all the aluminum 8.8 IRS housings Ford has ever produced. Be sure you get a 2007 through 2010 housing. Those are the ones with the massive front ears for locating the nose of the housing.

When ACE23 was struggling with the same decision alternatives you currently are I posted up some pics and suggestions for him on the site here. This is a link to the post => Ford 8.8 IRS Suggestions.

You might find something in there that could be helpful as you go about noodling out the best alternatives for your build.

BTW congrats on the decision to do a scratch build. It is the best way to get your Cobra exactly they way you always wanted and thought they should be — lots of work but also lots of satisfaction and immense pride in the finished product that is YOUR Cobra.


Ed

I can literally buy a half dozen of those today, and even better, it appears as if they come in 3.73, which was similar to the original competition cars 3.77 final drive ratio.

Thanks for the congratulations. It's been a very long time coming, and I've finally refined my goals in the build.

1. I want to learn about the processes and gather the tools necessary to scratch build a car
2. I want to end up with a 289 Cobra that not only replicates the look, but also replicates the "feel" of an original competition car
3. I want a "piddle around" business in my retirement where I build a car that interests me, play hard with it and then sell it to finance my next project. And I'm not in the position to become Jay Leno and actually buy and keep all those exotic cars I've always wanted.

All of this has been very helpful. Thank you very much!

Drew