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Discussion Starter #1
Does anyone know where the difference is in width for the Pin Drive vs. Standard IRS? I am wondering if they leave the control arms at the same length and narrow the cradle or if they leave the cradle the same but have shorter control arms.

I don't have a FF car (yet), but I really like the looks of this IRS and thinking of trying to put it into my 65 mustang.

I've read of others using the FF irs in their non-ff cars, but can't find any details on it. Any help/info would be appreciated!
 

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Pin drive vs standard has to do with wheel options. The LCA for the two are different in length and have different shock mounting tabs. The purpose for the pin drive width IRS is so that you can use pin drive hubs, enabling you to run functional knock off wheels. If you like the original halibrand wheels and want them to be knock offs, then you'd need p.d. IRS. If you don't care for functional knock off wheels, then go with the standard IRS.

You want to put this in a '65 Mustang? I'd go with a different IRS. Look into Control Freak suspensions. The design is very similar, however their suspension is designed to be modded into a Mustang. If you want to do the job right the first time, that's the suspension I'd go with. The 2 suspensions use the same core components, and both are very good systems, however one was designed for a 'Stang and the other isn't. IRS is only as good as the chassis around it, and the FFR IRS wouldn't match up with the rest of the 'Stang's chassis. Which is why the C.F. IRS is designed to beef up the 'Stang's chassis and make it a lot stiffer.

http://www.mustangandfords.com/techarticles/suspension/mufp_0606_classic_ford_mustang_independent_rear_suspension_install/photo_02.html
http://www.mustangsunlimited.com/itemdy01.asp?T1=CF120+01&Category=Suspension+&+Steering&subCategory=Idependent+Rear+Suspension&CatKey=EMUSTANG
 

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Discussion Starter #3 (Edited)
Thanks! I'm really not interested in the halibrands and since the difference in length is in the LCAs, I will focus more on the standard width and figure out how to narrow each side by an inch....or adjust the overall width by some backspacing magic.

Again, thanks for the info!



Just saw the rest of your comments.... I'll give them a look! I've been looking at several options, just trying to determine the best bang for the buck and i have heard a lot of good things about the ff IRS.
 

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If you want the best bang for your buck, you can't find a better IRS system than the one by Control Freak for the Mustang. They took the time to build it right for the intended application. FFR did a great job of designing their IRS as well, but for the intended application. If you do decide to go with the FFR IRS, I'd suggest beefing up the chassis so that it is similar to the C.F IRS. Because the two use the same platform, any questions you have about the 8.8" IRS can be answered right here. FFCars has hundreds of members that use that IRS and can tell you how well the core components perform.

The pin drive is the shorter of the two. I think it is about an inch shorter. Below is the standard IRS.

On the pin drive, instead of having the tabs for the hubs being horizontal to the LCA, the tabs are verticle. This makes it a tad shorter and lowers the shock mounting point about an inch. I'm not sure of the exact length you need for the 'Stang, but judging off of C.F.'s IRS, it looks like pin drive. They use the same diff and half axles if that helps you judge the length.
 

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Discussion Starter #5
Well, I just got off the phone with Control Freaks and they stopped making their IRS last year... So,...back to the drawing board.

I don't have an issue with beefing up the rear,...my largest concern is with the overall width, to make sure I can fit the IRS with wheels under the car without flaring the wheel wells or shortening the IRS control arms and adversely impacting suspension geometry.

Just rambling. Thanks again... If you have any thoughts I'd appreciate them!
 

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*EDIT* The pin drive is 5" shorter overall, or 2.5" per side. The UCAs, LCAs and axle half shafts are all shorter by 2.5". The pin drive shocks are also 18" instead of the 16" for standard width. If you want bolt on wheels, they bolt right up with the correct backspacing. If you want pin drive wheels, you will need the special adapter that FFR makes.

The IRS in the posted picture is standard width. To date, I have not heard of a FFR IRS failure.
 

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Discussion Starter #7
The pin drive is 2.5" shorter overall, or 1.25" per side. The UCAs, LCAs and axle half shafts are all shorter by 1.25". The pin drive shocks are also 18" instead of the 16" for standard width. If you want bolt on wheels, they bolt right up with the correct backspacing. If you want pin drive wheels, you will need the special adapter that FFR makes.

The IRS in the posted picture is standard width. To date, I have not heard of a FFR IRS failure.
The pin drive is only 2.5" shorter total? I thought the ff site had them listed at 54.25" vs. 59.25" for standard....so 5" total or 2.5" per side. If it is 2.5" shorter total, that will definitely fit my needs.
 

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The pin drive is only 2.5" shorter total? I thought the ff site had them listed at 54.25" vs. 59.25" for standard....so 5" total or 2.5" per side. If it is 2.5" shorter total, that will definitely fit my needs.
Damn, I must have added wrong. I knew the 2.5" was right...my bad.
 

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If you do put the FFR IRS in your 'Stang, keep us updated. I've seen a few cars with the FFR IRS in them somewhere on the net.
 
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