Is a NO-GO!!!!

Since I have already installed a panther front suspension, my ride height is set due to that front suspension.

Here is what happened. I got all the parts to put a 1993 Mark VIII rear suspension under my truck. I got the truck set level, and then set the Mark VIII rear suspension at ride height (the lower control arms are level), and when I lined them up and took some measurments, its was a whopping 3-1/2 inches too low at the rear mount, and the front mount would have only touched the frame 1/2 inch.

Granted I certainly could have made 3-1/2 blocks to take up the space, and I could have boxed the front mounts, and made a cross brace with exhaust and drive shaft cut outs. But that would have bee way too much work to run an IRS.

This could be a very great rear suspension for someone who is going to use a Mustang II front suspenion, as you could install the rear first and base the front off the rear ride height. You would have one very very low truck.


BUT I AM HERE TO SAY THAT THIS WILL NOT BOLT RIGHT UP IF YOU HAVE A STOCK SUSPENSION OR A CROWN VIC FRONT SUSPENSION.

 

.....and this would be a surprise???? Heck, I haven't taken too many parts designed for my pickup out of the box and had them actually bolt right up without some modifications........

 

No, not much of a suprise, as I said, it wouldnt be beyond me to make the blocks and the cross member support. Im just locked into a certain ride height due to the front suspenion and not wanting the rear suspension to appear out of place, as I feel it would with the mods to get it to bolt up.

 

What if I made a bolt in setup to adapt the lincoln IRS into the stock frame when using the 03-07 crown vic front suspension? If I build it will they come? pm me if interested

 

Ill let loose of all of the parts to do it for the cost I have in all the parts. I also have the parts required to covert the lincoln rear to 4.5 bolt pattern, which were not cheap.

Like I said, its not something that I coudnt do, but the way it was going to look, I feel it would have been out of place, IMHO. But for someone who wants the cool factor of a ford IRS, and has the time to make this look right, its for sale. Ill work on getting it shipped too.

Im sure an bolt in setup could be made, some rear 3-1/2 blocks, and a front boxing/drive shaft loop, it would work.

 

So, if I understand this right, to install the IRS setup as intended with the conversion brackets, you would have to lower your front Grand Marquis front suspension 3 1/2" to level it out? Wow, that would be low, and real cool to. I don't think the roads in my area would allow such a mod, but I sure do like the idea!

 

So what kind of rear suspension are you gonna run now? Maybe a triangulated 4 link? then I could see what you did and copy it

 

Blue Oval -- Yup, essentially, thats if I wanted to mount the IRS to the frame. I suppose that one could notch the front frame then install the IFS. Depending on the motor choice, you could use the CV motor perches, or make your own off the boxed area of the frame.

Carcrafter -- Im going to stick with the stock rear, I want to upgrade it to the 4.5 bolt pattern, so unless I can find a shop locally (so far a challenge, despite being between E-Town and Atco raceways) to redrill my axles, off to Moser they will go.

Once I get some money saved up, I will install a triangulated 4 link with an Air Ride system.

 

When you set the IRS in place, you said you had the control arms level. I found the better setup is to have the differential centerline sitting 1" higher than the wheel center line. This would rise the subframe closer to the frame. At this setting, it will allow 5" of drop and 3" of rise from ride height.
Also, the installation instructions from truckIRS.com shows installing the subframe level, front to back. That's fine if the engine and tranny are sitting level. The differential needs to be installed at the same angle as what the tranny is sitting, to minimize the driveline vibrations.
This is how it is sitting in my truck.

 

Actually I work for a company that builds cvj (constant volicity joints ) for most of the industry and the design of the cvj ends are made so that they are supposed to wear on the full pattern of the joint , not in one spot . If the cvj bj (usaully the wheel end ) was set at a straight angle the ball track would wear a pit in the track causing it to fail early when it ran at a angle (turning the wheels , suspension wear , ball joint movement ). Usaully the tranny end (or doj , tj , several others ) will plunge for suspension travel and this is the actual reason for the cvj design . (basically if the wheel end will fail early if it is set perfectly level with the rearend ) Finding the correct angle would be ideal .

This is what I was taught in a class when i first hired in 18 years ago . sorry to run on but it may help . Im not 100 % that this rearend is like this , but we do make shafts for other irs , front wheel , and all wheel drive perfomance cars . (new cars ) thanks rg

 

That one of the reasons I set the differential 1" higher than the wheels. Same applies to universal joints. You should have a minimum of 1 degree across the joint, so there is always movement in the bearing to keep them lubed.
I have roughly 30,000 miles on the IRS since I put it in and the halfshafts are original from the car. It has been 100% trouble free.

 

i agree that your setup is alot better than level with the differintial . thanks rg

 

Hey Sportruck,
Lets see some pictures of that irs installed.

 

I have a gallery of pics from start to finish, but here's a couple.

IRS Axle pictures by Sportruk1 - Photobucket
Pictures by Sportruk1 - Photobucket





A before and after of the truck.

 

That is some awesome fab work there! I have a friend that is working on a design bolt in front and rear A-arm suspension for these trucks. A shortbed 67-72 F100 canyon carver would be GREAT! Thanks for sharing those pics.
-Lance