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Frequently asked Questions – FAQ’s

What is the price of the truck IRS Adapter Brackets?
$395 plus shipping… flat rate US Postal Priority mail costs $35 in the Continental US…

How do I pay for a set of truck IRS Brackets?
We accept Personal Checks, Cashier’s Checks and Money Orders. We also accept paypal. For more information…Call (321)960-5945 or email dave@team321.com

Who is Team321 LLC and what do they have to do with TruckIRS?
Team321 LLC is the parent company. TruckIRS.com and the truckIRS product line has become synonymous with Independent Rear Suspension packages for Classic Ford and Chevy trucks.

I would like a set of brackets for my car or truck, but it’s not a 1948-79 Ford. How can I get IRS Adapter Brackets for my vehicle?
We can make brackets to adapt the T-bird / Cougar / Lincoln Mark 8 IRS subassembly to a wide variety of cars and trucks. For a full explanation, click alternate frame adapters.

What size wheels / tires can I use with the truckIRS rear suspension kit?
Based on the photos on truckIRS installation procedure… There is about 2″ between the inside of the tire and the outside of the truck’s bed… this is shown with the fender removed… so to be safe, I wouldn’t to any closer than 1.5″

Further down… with the fender installed, there is about 1 1/2″ of clearance between the outside of the tire and the fender lip… so let’s call it 1″ to be safe.
Having said / seen that, I conclude that you can use a tire that is 2.5″ wider than the factory lincoln mark 8 tire with the same wheel offset… Lincoln used a 38-40mm offset rim and a 225/60-16 tire.

225mm + 2.5″ = 8.86 + 2.5 = 11.36 inches = 288.5mm
so a 275 width tire will fit the rear.

What is the track width of the T bird / Lincoln rear suspension?
I measured the hub – to – hub distance on a Lincoln IRS and found it to be – 63 1/4″

I also measured a T bird rear suspension with tires / wheels installed – The Outside / Outside tire measurement is about 66 1/2″ ( using the factory T bird wheels / tires ).

The spec’d track width of the Lincoln Mark 8 is 1,529mm or 60.19″ – but track width is a funny thing – since it is a measurement from the center to center of the tire… which is only useful if you have the tire and wheel ( especially offset ) info… which is usually not given… The only offset info I can find online indicates it is 38 – 40mm. With this in mind, the calculated hub-to-hub measurement is 63.25″ which compares favorably with my measurement.

What type of truck does the IRS adapters work on?
The IRS adapter kit has been proven to work on Ford Trucks ranging from 1948 – 1979, 1955 – 1959 Chevy Trucks and Ford Ranger trucks.

My truck is not a 1948 – 1979 Ford truck, but I want to install your kit – what are my options?
We are developing new kits all the time, quite often a prototype or early production solution is available long before it appears on this website. Call (321)960-5945 or email dave@team321.com with your ideas and we can work on a solution.

What is the best car to get the IRS out of?
That depends on what you mean by the best… Any 1989- 1997 Thunderbird or 1993 – 1998 Lincoln Mark 8 has an IRS that will work with these adapters. All Lincolns feature an Aluminum Differential – which looks better and is lighter than the cast iron piece found in the T-birds. Some T-birds have rear disc brakes, some have drum brakes… all Lincolns Mark 8s have rear disc brakes. It is best to get an IRS out of a V8 powered car since the axles are stronger than the V6 axles.
Lincolns have air bags that may or may not be used with an aftermarket airbag compressor / controls / etc…
The Lincoln air bags can be replaced with coil springs, or aftermarket airbags with matching compressor / controls… click here for more info on airbag installation.
If you prefer coil springs to air bags, look for a V8 Ford Thunderbird with rear disk brakes. If you would like to use aftermarket airbags, get a Lincoln Mark 8 and I can recommend airbags and provide all other pieces you need. More info on airbag installation may be found HERE.

What is the bolt pattern of the Tbird / Lincoln rear hubs?
5 on 4.25″ (5 on 108mm) is the original bolt pattern.

I How do I change the bolt pattern to 5 on 4 1/2″
The 1999-2004 Mustang Cobra IRS uses a rear hub with the 5 on 4 1/2 bolt pattern that is compatible with the Mark8/Tbird rear spindle. Click here for details on changing the hub to 4 1/2″ bolt pattern.

What kind of wheels will fit on the rear after I install the Thunderbird / Lincoln IRS assembly?
The original T-bird or Lincoln wheels will fit, of course, but 5 on 4.25″ or 108mm and there are aftermarket wheel options for 4.25″ or 108mm bolt pattern. When shopping for wheels online, simply select 1996 Lincoln Mark8 when asked to select a vehicle.

How long should the installation take?
The total install time will vary with the experience / expertise of whoever is doing the job… but on average it will take 2 – 4 hours. The vast majority of the time will be spent measuring the wheelbase, alignment, etc… prior to welding the adapters to the frame. This procedure can be done on any flat, level surface – but it is time-consuming. This time estimate assumes the truck bed and the original rear end has been removed.

Will the truck bed fit on top of the new IRS once it’s installed?
Yes, the new IRS does not interfere with the frame nor does it interfere with the bed.

Can I use the factory T-bird coil springs?
Yes – but they may need to be cut ( shortened ) in order to get the desired ride height. When cutting springs, only cut 1/2 coil at a time. Cut 1/2 coil, reinstall the springs and see if the ride height is where you want it. If you want it lowered, cut another 1/2 coil.
Another option is to use sport springs that are designed to lower the T bird’s ride height. I do not have a current vendor for lowering springs, but if you find one – please let me know.

Can I use coil springs with the Lincoln Mark8 IRS subframe?
Yes – I recommend Suncore Industries – CLICK HERE for more info

What about air springs / air bags?
Team321 has airs pring adapter pedestals that fit the Lincoln Mark8 or Tbird / Cougar Lower Control Arms and can recommend the correct airsprings for your application.
More info on using air springs with the TruckIRS installation may be found HERE.

What about the front suspension? Do you make a kit for the front as well?
We sell kits to mount the factory 2003 -2009 Crown Victoria (Crown Vic) front crossmember in Ford Trucks from 1953-1995… Click HERE for more details on our Crown Vic front mounting kits.

But we also have a Narrow Track Width Crown Vic Front Suspension Crossmember that uses the Crown Vic suspension and brake components –  Click HERE for more details on our Narrow Crown Vic front suspension options.

What other products does Team321 make?
We manufacture a variety of custom front and rear suspensions… most of them are represented on team321.com – but much of the custom work is not. Call (321)960-5945 or email dave@team321.com with your ideas and we can work on a solution.

For more information…Call (321)960-5945 or email dave@team321.com

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