IRS Center Section Option #206338

[cv2065]

Anyone have this option and know the finer details? My last build I don't recall this being offered, as I sourced my own IRS, spindles and hubs from a takeoff pallet buy that had 100 miles or something like that. This option is $1750. I'm assuming that the 2018 IRS center section, hubs and spindles are all brand new? Would that be an iron or aluminum center section? Does FFR install the IRS since it's coming with the kit? I sent a note to CS, but thought someone might have experience with the option. Thanks.

[michael everson]

the $1750 covers the iron center section, 2 new spindles 2 new hubs and mounting hardware. Not a bad deal but the parts can be sourced used much cheaper. I have seen pumpkins as low as $300.00 I bought spindles on Ebay for around $100.00 per side. FFR does not build the IRS option. They do change the whole back of the frame to accommodate it.
Mike

[narly1]

Adding that if you order the frame set up for IRS that you get two custom half-shafts made to fit the FFR application as part of the deal.

Earl

[cv2065]

the $1750 covers the iron center section, 2 new spindles 2 new hubs and mounting hardware. Not a bad deal but the parts can be sourced used much cheaper. I have seen pumpkins as low as $300.00 I bought spindles on Ebay for around $100.00 per side. FFR does not build the IRS option. They do change the whole back of the frame to accommodate it.
Mike

Thanks Mike. Yes, I sourced mine myself the last build. I think I paid $1400 shipped for a very low mileage pull. Is the IRS center section from FFR new?

[cv2065]

Thanks. That was one of the questions I asked FFR. I thought I had new half shafts when I purchased the option last time around but couldn't remember. Didn't know they were custom to FFR.

[CraigS]

For me, the advantage of going w/ a salvage yard take out is free brakes. See all the posts here w/ Qs about the rear brakes? I avoided all that crap, got brakes that fit perfectly with a builtin park brake that works perfectly. These are NOT like the old Fox body or Lincoln or T-bird rear discs. Mine even included the park brake cables which I spliced (w/ 2 cable clamps each) to the front most 15 inches of my old cables so no adapters needed. BTW Hawk, and all others, make pads in nearly all their compounds for a 15 Mustang. I just don't understand why more people don't do this.

[narly1]

Thanks. That was one of the questions I asked FFR. I thought I had new half shafts when I purchased the option last time around but couldn't remember. Didn't know they were custom to FFR.

I can't say with 100% certainty that the half shafts are custom but my instincts tell me that the it would be too much of a coincidence that all of the various FFR platforms would be the same width as the Mustang.

That and the fact that FFR never says anywhere to use donor half-shafts / and that they sell their own pieces.

Earl

[BRRT]

I hit up the local junkyard, got a differential out of a 2019 Mustang, 3.55, Torsen for $300. It has 52,000 miles on it.
I did a thorough cleaning on it and painted it.
Got new halfshaft seals at the local Ford dealer. I can't recall the price.
I bought new rear knuckles with hubs from Summit for $500.
The wheel studs were under $20.

Quite a savings!

[TBull]

The half shafts from from FFR are only rated at a certain HP. I think the ones for my old 8.8 were somewhere around 400 HP. My intent was to be significantly higher than that, so I bought upgraded half shafts form the Driveshaft Shop. They were designated to be FFR length, which tells me it is a custom length. I still have the originals in a box somewhere.

[edwardb]

Maybe to restate what has already been said -- but what Factory Five is selling for the IRS parts are standard Ford Performance catalog parts: M-4001-88355B 8.8 iron case center section, 3.55 ratio, standard clutch type Traction-Lok; and M-5970-M knuckles/hubs. If you want new, you can shop around and probably save a little. As already mentioned, lots of parts in salvage now. Including different ratios, Torsen vs. clutch locker, etc. So options there with the usual risk for used parts.

The CV axles that come with the IRS option are a custom length, but have standard Ford CV joints on each end. The Ford part numbers are clearly visible. Unless you're at really high HP, sticky tires, and aggressive launches, doubt very much with this weight car you're going to break them. There have been no reported failures of the CV axles in the now nearly 8 years they've been offered. I know that's not a scientifically supported statistic. But failures of any kind are usually reported on the forum.

[herb427sc]

I got half shafts from the Drive Shaft Shop last year.
These were for the early T-Bird IRS conversion.
Rated for 800 Horsepower.
Just over $2000 delivered for 2 half shafts.

[rich grsc]

I got half shafts from the Drive Shaft Shop last year.
These were for the early T-Bird IRS conversion.
Rated for 800 Horsepower.
Just over $2000 delivered for 2 half shafts.
Did you have to call them to get the correct length? I see the T-Bird listed, but nothing custom for FFR

[Junbug]

Thanks Mike. Yes, I sourced mine myself the last build. I think I paid $1400 shipped for a very low mileage pull. Is the IRS center section from FFR new?

Yes the center section is brand new, shipped in a OEM Ford box.

[herb427sc]

Did you have to call them to get the correct length? I see the T-Bird listed, but nothing custom for FFR

If you look at the website for Drive Shaft Shop there is a tutorial on how to measure for correct length.

[TBull]

When you call them just tell them it is for a FFR roadster. They know the length. I specifically bought the upgraded half shafts after talking g to another autocrosser with a supercharged 331 and he had snapped one of his original half shafts. I just decided to avoid the issue. As Paul pointed out, if you aren't high horsepower, you probably don't need them. That includes you Rich. ;)

[cv2065]

Thanks again for all of the replies. I did the math for a new IRS center section, spindles and hubs and comes out to about the same price as what FFR is asking versus buying separately.

Does anyone know how much HP the half shafts are rated for? I read somewhere that it's about 500hp, but is that to the wheels or crankshaft? I don't plan on tracking but may run between 500-600HP to the crank with a 427 or Godzilla engine.

[valin]

There are Mustang guys running over 1000hp on the street with the oem 1/2 shafts. You should not have an issue with that kind of power.

If you would like information on doing a Godzilla in one of these, hit me up. It is a pretty costly endeavor.

[cv2065]

Thanks Ryan. Holley just came out with an oil conversion kit for the Godzilla that's about a quarter of the price of the Indy Products. There are a few other aftermarket companies that offer low profile pans as well. Seems like some 3rd parties are catching up and bringing down the price. I've spoken with Forte and he's looking into creating some mounts and other fitments. Might be a reality very shortly for anyone with an FFR Roadster that wants to bring a Godzilla home!

[BRRT]

FYI, I had my final kit review with the folks at FFR this morning. The center section, hub and knuckle option is just that. All new Ford parts, except the studs, which are Dorman. When you specify rear independent suspension (Item 17120) you get the necessary frame mods, fasteners, rear half shafts, and everything else to build the rear suspension.