Seems like the Thunderbird. Cougar, Mark VIII appear on craigslist.com in spurts. I decided on the Mark VIII. I thought maybe less chance on someone wearing out the rear end by dragging as in T-bird(I had a 97). The 1993 Mark VIII had a V-8. Early cougar and T-birds had V-6's and I couldn't find a good site on what years did what. Also the Mark VIII had air bags, etc. I could always find rear springs from a T-bird of cougar. I don't know if V-8 and V-6 used the same springs. The rear IRS cage mount might need a second cross frame member as I think the spring is going to give a lot of upward stress against a thin frame, maybe not, but I think I will add a extra cross member. Easy install and has sway bar. As for the front IFS the upper A-arm mount to be made is the trick. As others said waiting for experts do do one and show pictures. Have a great day,chuck

 

When I first became acquainted to this forum I asked about putting the Super Coupe running gear under my 50 Panel and there wasn't anyone out there that had tried it. That was four years or more and now there are convertion kits for the IRS and hopefully someone is working on the IFS. If I didn't get side tracked by other projects maybe these suspensions would be under the truck and it would be rolling. Thanks for all the great input and patience.

Gear Up

 

Can anyone tell me for sure. Do the 89-97 thunderbird, cougars, and mark VIIIs all have the 8.8" rear-ends? I thought this was the case but someone tried telling me today that the regular LX t-birds have a 7.5" rear-end and that only the Super Coups came with the 8.8". Does anyone know the real answer?

Thanks

 

Make sure to get the rear from a T bird / Cougar originally equpped with a V8 engine. The V8 powered cars came with 8.8 rears.

dave
Cocoa Beach FL

 

Thanks Dave!

 

Dave
How do you adjust the pinion angle with your kit? Also what is entailed with converting a Tbird rear end from drum to disk brakes?
Thanks
Scott

 

The short answer is to set the frame at the selected ride height, position the IRS subframe ( prior to welding the adapter brackets ). Bolt the subframe adapters to the subframe to position the subframe at the desired pinion angle, then weld the adapter brackets into place.

I use 6 or more angle finders located on the truck's frame, the subframe, etc... to assure proper positioning prior to ( and after ) welding.

Minor adjustments can be made with shims between the subframe and the adapters after the assembly is welded in place.

Full installation instructions are available showing this process.
dave

 

The easiest way to convert from drum to disc is to replace the entire drum-style spindle with a disc-style spindle... spindle, rotor, caliper, etc...

The second option is to remove the drum, bearing, etc... and machine the drum-style spindle to mount the caliper. The machining involves drilling holes in the correct location to locate the caliper and machine the caliper mounting surface flat... The last step is to remove material from the spindle that would otherwise interfere with the caliper.

more info to follow immediately below...
dave



What type of brakes are available?
All Lincoln rear suspensions feature rear disc brakes. Some T -birds and Cougars have disc brakes, while others have drum brakes.
Either style of brakes will work... but disc brakes are preferred since they have greater stopping power.

I have a rear subframe from a T-bird with drum brakes... can I change the brakes from drum to disc brakes?
Yes, there are a couple of options. The first is to locate spindles with disc brakes, calipers and rotors... then remove and replace your drum brake spindles with the disc brake spindles.
They are interchangeable.

The second option is to modify the drum brake spindle to utilize a disc brake caliper and rotor. This is more difficult than simply swapping spindles, but it is possible.

Sounds like alot of work... why don't you just buy a subframe with disc brakes?
Agreed... buying a complete unit is the best option, but often there are only drum brake subframes in local wrecking yards... yet disc brake spindles are available all over the country. Since it is far easier ( and cheaper ) to ship a pair of spindles and brake components vs. an entire subframe - the option of buying a subframe locally and a pair of spindles through the mail is the best option.

 

Thanks Dave.
What about converting drum brakes to Disk? Is that just a matter of changing the backing plates and adding rotors & calipers?
Scott

 

We put a IRS rear end from a 1995 Thunderbird in our 1948 F-1 truck. We made all the mounting and it works great. You need a machine shop and good tig welding to do it yourself. We also made all the mounting to put the front end in the truck.

 

mytbtruck
Do you have any pictures of how you mounted the thunderbird front end in the truck?

 

It took a lot of fabricating parts to do this but you can see some of the pictures at smokemup.com. Click top menu on garage, left side menu browse garage and scroll down to 1948 F150. Click on F150 and let me know if you have any questions. The main thing was getting correct caster. We have a gauge and set it before we welded anything in place. The side frame pieces extended the frame to give the correct mounting with the 4 original holes in the K member. The wheel base on car was 113 and the truck was 114 so we were able to use the drive shaft as it was. It has been a fun project and I will get some pictures when we start final assembly. Thanks for asking.

 

Very nice project!!!

 

Dave
Do you need to worry about the caster when installing the Tbird IRS? My guess would be that you would want to mount the axis of the lower control arm Parallel to the ground. Is that correct?

 

I have the IFS out of a 1995 T-bird in my 48 frame. The main thing to consider is the caster angle. I think it is about 5.5 in the T-bird. You will need some type of gauge to measure caster. Camber and toe are easy to get close enough to have enough adjustment . I think we ended up adjusting caster around 5 and that drives very good. I can post a picture to show what I have if you need it. It takes some machine work and good tig welding to get it right. We extended the width of the frame with a 1 inch flat solid steel plate to mount the IFS on and replaced all the cross member and added a few more and boxed the frame for stability. I also have the IRS mounted in the truck. The IFS made it very convient to use the 4.6 V8 out of the T-bird and also had rack and pinion power steering already available.