90s thunderbird rearend or 90s jaguar?

[JumboAMONGus]

what is better ? and stronger? i find these on craiglist all the time and seen peoples build threads using them just wondering peoples thoughts ,on it plus same cost as 4 link but looks cooler

[G&R's57GMC]

Think repair parts, bolt pattern. Ford Si , Jag No

[mr48chev]

The Jags usually have a 5 on 4-3/4 bolt pattern (familiar?). These days there enough Jag sedans floating around that parts should be a lot easier to get than when guys were running XKE independents in their rods.
Most of the T birds with independent rears were V6 cars or small block cars that weren't noted for excess horsepower so I don't know how they actually stand up under hard driving. They are easy enough to find and inexpensive enough so a guy could swap one out and be gone if needed though.

I'm still a serious advocate of putting parts on your rigs that have wear parts that are somewhat simple and easy to get though. That is one reason 9 inch Ford rear ends have been so popular for so long. Any back street shop with a hydraulic press can swap and axle bearing an the third members can be dropped out and replaced in short order even if the gear ratio that is being put back in isn't the best it will get you home and then some.

[solidaxel]

Like the service writer at the Jag store told me when i went in to buy a parking light bulb for 21.00, "expensive cars expensive parts"

[fredscarryall]

i have a thunderbird/lincoln mark 8 independent rear end in my suburban.i found that most of these sell for about $250 to $300.i got mine with a 3.27 posi.i have about 600 mile on mine and almost 400 horse so it holds up to horsepower just fine.the biggest problem is the bolt pattern.its a 5 on 108 and i could only find ugle factory wheels to fit. so i had to change the bolt pattern to a ford 5 on 4 1/2.first you have to remove the hub assembly from the upper and lower control arms. they should come out with a little force.then you have to take them down to a engine machine shop with a heavy duty press to press the the hub from the bearing.you cant use a home garage press because it will bend it.most shops will charge $50 to press both out and another $50 to press both in . you also have a 50% chance of crushing a bearing. the bearings cost about $50 each. then you need to take the pressed out hubs to a machine shop and have the hub drilled and tapped to the 5 on 4 1/2 bolt pattern(you cant drill it to a chevy 5 on 4 3/4 because its to big)the mchine shop will charge you $50 to drill both hubs and another $50 to tap both hubs.you can use the factory studs.so it could cost about $300. but there may be another route to the irs check out the next post.

[fredscarryall]

i forgot another $50 to have rotors redrilled.if you have the room and dont mind wheel spacers ebay sell wheel spacers 1 1\4 inch that go from 5 on 108 to both 5 on 4 1/2 and 5 on 5 on 4 3/4 for about $40 each. then you can go to truckirs.com (team321). they sell a prefab kit for about $395 to use the thunderbird irs.they have conversions for chevy 1948 to 1959 trucks.they also claim you only will have about 2 hours of welding. the site has very helpful info. hope this helps you out and anyone considering the conversion.just make sure if you buy a thunderbird/lincoln irs you get everthing. form shocks or air bags and cups,all nuts,bolts,driveline and even the ebrake cable all the way to the handle.

[shadow1967]

Be careful! I was looking at that rearend for the same reason, But think of upgrades..
Mustang hubs, disc brakes and differential. Most lincolns were peg leg.

[fredscarryall]

alot of the regular thunderbird/lincoln where one wheel peels.the higher end lincolns mark VIII LSC and thunderbird turbo coupes where all posi units.the easiest way is to check the rear end tag.it looks like this one.the L means traction lock which is fords posi. and all of them should have come with disc brakes. but make sure you get the 1989 to 1997 years.they made 700,000 of these car for 8 years in just thunderbird alone. so anyone looking for a posi should just hold out till they find one.

[JumboAMONGus]

i was looking threw craiglist and there is tons of the couger thunderbird rear clips for sale for cheap , and jags ,,so look for an L and im good to go on posi , now do they pretty much weld in between the frame and the a bracket fo the shocks and springs ? or was there alot of fab work ? plus are the covers aluminum or steel

[fredscarryall]

i think the tuffiest part is figuring out the ride height and cross measuring to make it line up straight.you may want to box the frame where you weld the brackets to the frame. i dont think it is nessecary to box the entire back half of the frame.im not sure what you mean by cover.for both the lincoln and the t bird center sections (pumpkin) and the pumpkin cover are aluminum and if you get a lincoln irs the lower control arms are cast aluminum also.the rest of the components are steel on both.here some pics. the first one is the thunderbird with coil spring set up made of cast metal and the other two are lincoln with the air bag set up made of cast aluminum

[JumboAMONGus]

yes i ment diff cover and lower arms , thats why i like the lincoln ,, be nice to get it all shot peened .probly be good to get front ifs first then do rear or you think rear first before front ? what years lincoln all fit ?

[fredscarryall]

for the lincoln mark viii your looking for 1993 to 1998. you need to do the front end before you do the rear.

[Coach529]

Digging up this thread because I would love to put in one of these rear ends in Henry.

Any more info??

[e015475]

The Lincoln IRS seems like a pretty cool setup and is a lot more modern than the Jag. There seems to be a misconception that the Jag stuff is expensive, but the aftermarket has served this market for so long, there is no need to buy anything from the dealer for these IRS.

Here's a list of the pros of the Jag IRS-

- The XJ6 sedan IRS to '86 are the Chevy bolt pattern (maybe later too) and all the XJS coupes/convertibles have the early GM pattern. I usually pay between $200 and $300 for a Jag IRS
- The width is very close to the AD truck factory width
- The diff itself is basically a Dana unit and all sorts of gear sets and carriers are available. My local 4WD shop had all the parts for mine. To buy a carrier new is about $300 and the gearset is about $200. For labor, YMMV, but I paid about $200 to have the last one setup
-U-joints are standard GM and about $10-12 each.
-Camber can be adjusted with a level by removing four bolts and adding or deleting shims. Piece of cake.
-They look cool - very old school, IMHO

Here's the cons-

- The design is from the late 40s or 50s - it is ok, but the Lincoln probably has better geometry
-The brakes are usually inboard against the diff. While this looks cool, it cooks the seal out of the diff eventually. Changing the rear brake pads is a PITA, and it is usually easier to drop the rear end out of the car to change the brake pads or calipers.
-The Jag's IRS is supported by four coil over shocks about 11" long. Replacing the coil overs can easily run $500 and options for shocks and spring rates are limited. Packing a coilover in an 11" package doesn't leave much room for suspension travel on a truck
-Putting conventional airbags on a Jag IRS requires a lot of fabrication and the impact on the suspension arm bearings is questionable. You can use those shock/airbag thingys, but they are pretty spendy.
-The garden-variety diff ration is 2.88 and will be from an XJ6 sedan without limited slip. Locking diffs in factory cars with 3.54 ratio can be found, but only in XJS models with the straight six, which I think is from '90 to about '96. (These will have outboard brakes too) They are around, but you'll have to look a lot longer to find one
-I've heard that towing with a Jag IRS isn't pleasant, but I have no personal experience here but throwing it out there anyway.

Good sense would indicate that the Lincoln IRS would be a better choice. But my truck is just me being nostalgic about things I grew up with and thought was cool and I only now have two nickels to rub together to have a playtoy- so I have a Jag IRS in my '49

[Coach529]

I have pretty much google searched it to death today......and I like what I see. The Ford/ Lincoln version is readily available. Ratios are what I am looking for. Limited slip is out there. Converting to air bags and ditching the coils looks easy.

[Coach529]

[Rickysnickers]

If you are going to do that much fab work, look at the IRS out of an '03-'04 Cobra. They are stronger than the T-bird units, and I believe they have a similar mounting style.

[Coach529]

Originally Posted by Rickysnickers

If you are going to do that much fab work, look at the IRS out of an '03-'04 Cobra. They are stronger than the T-bird units, and I believe they have a similar mounting style.

Select T Birds have 8.8 rear ends and are limited slip. I can find these locally for less than $200.00.

The Cobra will bust my budget and be like trying to find a needle in a haystack.

I do not for see anything higher than 300hp out of this truck.....the 8.8 will be fine.

As far as fab work, this looks like no more work than installing a 4 link. Seems pretty straight forward.

[ghettoluxury]

That looks like a clean and easy install. Go for it!

[Coach529]

Originally Posted by ghettoluxury

That looks like a clean and easy install. Go for it!

Thanks!!

[BIGglaSS]

I looked into the lincoln IRS. I was going to do it until I found a good deal on a couple C4 rear ends. Anyway, every lincoln IRS that I found had a 3.07 open rear. By the time I converted the bolt pattern ($), added limited slip ($500), and changed the gears ($180), it adds up quick. But, I wouldn't hesitate do do the swap. It will be a lot easier to airbag it!

[Coach529]

Originally Posted by BIGglaSS

I looked into the lincoln IRS. I was going to do it until I found a good deal on a couple C4 rear ends. Anyway, every lincoln IRS that I found had a 3.07 open rear. By the time I converted the bolt pattern ($), added limited slip ($500), and changed the gears ($180), it adds up quick. But, I wouldn't hesitate do do the swap. It will be a lot easier to airbag it!

I agree if you have to change the things you mentioned it would not be worthwhile.

Although I am hoping to find a Limited slip, and open diff would be acceptable for me.

3.08 gears is exactly what I am looking for. Henry is just a cruiser.....