Posted By: Explodo
Mopar IRS - 04/04/11 08:26 PM
A couple of years ago I posted about Blue Moon Motorsports making an IRS for mopars. That's definitely dead as of January of this year. With Heidt finally fixing their IRS to have an upper control arm, that looks to be a possibility, though one with a little bit of fabrication involved.
Does anyone know of any other routes to an independent rear on a classic mopar? I don't care about drag racing at all, so typical "IRS = bad for drag" concerns are moot.
Posted By: RodStRace
Re: Mopar IRS - 04/04/11 09:35 PM
Have you looked at Vipers and LXs?
Posted By: Explodo
Re: Mopar IRS - 04/04/11 09:54 PM
I'm okay with taking partial bits, like I'd have to do on the new Heidt thing, and then adapting it to work for me, but I distrust my ability to properly build a complete cradle that includes all mounting points for the arms and everything.
My impression was that for the LX or Viper rears I'd have to build everything. Am I incorrect in that? Are they sub-assemblied enough that just an adapter need be fabricated?
Edit: Okay, the LX is a subframe, but I can't find a complete picture of one anywhere. Anyone have a link?
Posted By: slantzilla
Re: Mopar IRS - 04/04/11 10:57 PM
There was a kid on here who put the IRS out of an early '90's Thunderbird under a '66 Dart or Valiant. He had lots of pictures, maybe he will chime in.
I think the IRS out of a Lincoln Mark VIII is what you are looking for, I believe they have a cradle system. Also, I thought about using the IRS out of 88-89 Conquest/Starion. This rear might not hold as much power as the 8, but it is Mopar (well, sort of)
Posted By: Cudajon
Re: Mopar IRS - 04/05/11 01:26 AM
The Lincoln is a great choice, plus parts can be found, comes with discs and the bolt pattern is 4.5 just like your Mope. Less than 2 bills at pull-a-part. Get everything.
Posted By: finadk
Re: Mopar IRS - 04/05/11 02:48 AM
I looked into doing something like this for my 56 Dodge. I thought that the ford setup seemed clunky and modifying the width of the cradle created complications. I dont like the inboard brakes on the Jaguar setups that much. Corvette C4 components seem to be about the best option.
Here is a link to a real nice setup 57 Chevy from the tri-five website that can give you some good ideas on what can be done. There would be a fair amount of fabrication involved but its is doable.
http://www.trifive.com/forums/showthread.php?t=30205 Scott
Posted By: DAYCLONA
Re: Mopar IRS - 04/05/11 03:03 AM
You should also consider track width, the LX is better suited for the 71-up B bodies, the 90's Thunderbird is better suited for early B (66-70) or 70-4 E bodies, the LX is a fragile unit in comparison to the Ford platform, theViper unit is nice, but look forward to a lot of fab to install it, as well as modding the unit itself, depending on your track requirements
Posted By: HotRodDave
Re: Mopar IRS - 04/05/11 03:40 PM
The cool thing about IRS is the ability to plant the tires without even haveing an LSD now if you add one it will really help. Think about it, the reason a live axle open rear wants to spin the right rear tire is the tq from the driveshaft is lifting that side of the axle and planting the other, with an IRS suspension the suspension moves instead of the whole axle picking up the right side. The lifting/planting action is lost in the CV axle. Even with no LSD they hook nearly as good as a straight axle.
Posted By: None2Slow
Re: Mopar IRS - 04/05/11 05:03 PM
That Ford rear is an 8.8 rear with 4.25 bolt circle. The cobra hubs will bolt on and give you the 4.5 you want. Not all tbirds had the 8.8, but had the 4.25 bolt pattern. The standard v6 had a 7.5. The SC v6 birds had the 8.8 traclok rear. Not all v8 birds had the 8.8 and if they did, may not have had traclok. If you go to
www.sccoa.com you will get all the answers you need, including dementions.
I think the C4, Dana 44 is your easiest to fab.
Granted, the trailing arms will limit tire/wheel width a little bit.
Also, the later 88-96 are a bit wider so you'll need more positive offset wheels. Or you can narrow the driveshafts and get custom tie rods/link arms from Vette Brakes.
Posted By: dirt
Re: Mopar IRS - 03/22/12 08:30 PM
i have used the corvette C4 IRS in street rod projects. I have a jig set up to make the rear frame section with the attaching points for the C4 stuff. it works pretty good.