Finally getting around to GT350R spring install, but which of these parts should I use?

[Dave TBG]

I've had a pile of parts gathering dust since last spring (details in sig) and I've come to grips with the fact that I won't be installing them anytime soon. I'm going to look for a shop to do the work and I'm inventorying the bits and pieces in preparation. I'd originally combed through the part numbers searching out all the correct part numbers for a GT350R so as to have the complete system. Then I went and ordered the M-18000-F strut/shock package, not realizing that it included the bumpers and lower spring isolators. So, which should I use?
I have the FR3Z-8321-B lower isolators that should be correct for the GT350R and DG9Z-8321-A that came with the struts/shocks. I haven't opened the packages to see if I can even tell the difference, is one prefered over the other?
Likewise, I have the FR3Z-3020-B and FR3Z-5K570-C bumpers, but there are already bumpers installed on the shocks and struts. I can't see them up under the dust covers well enough to see if they are the same. I have to assume that the GT350R parts are the correct length for the ride height of the springs. Any thoughts on this?
Whichever parts I have leftover will probably just end up in storage, it's not like I have enough cash tied up to put much effort into recouping it, so I'd just like to make sure I don't install something I'll regret.

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[Dave TBG]

Just an update, I decided to work backwards and googled the part number for the isolators that came with the M-18000-F. The part seems to fit a number of Fusions, an MKZ and the EB with automatic trans.I have no idea why the package would include these isolators, I'll be using the other ones.
I guess the next step is to pull the bumpers out of the struts and shocks and compare them to the other ones I ordered.

 

[BmacIL]

Just an update, I decided to work backwards and googled the part number for the isolators that came with the M-18000-F. The part seems to fit a number of Fusions, an MKZ and the EB with automatic trans.I have no idea why the package would include these isolators, I'll be using the other ones.
I guess the next step is to pull the bumpers out of the struts and shocks and compare them to the other ones I ordered.

Pretty sure they're actually the same, but with a different service vs production part number. You're fine with whichever you choose.

 

[BmacIL]

Those look like bottom vs top...

 

[Dave TBG]

Those look like bottom vs top...

You are correct, I grabbed the wrong picture. The isolators are pretty identical, it's the bumpers that were different,

 

[Dave TBG]

If I read the number on the bumper correctly it's FR3C-3K100-AA. This should be the same as FR3Z-8321-A, the bumper user on most S550s with 17-19" wheels. The part I found to be correct for the GT350R is FR3Z-8321-B, but the post I just found here on M6G says that is for S550s with 20" wheels and the GT350, non-R. That post lists FR3Z-8321-C for the GT350R.

 

[BmacIL]

If I read the number on the bumper correctly it's FR3C-3K100-AA. This should be the same as FR3Z-8321-A, the bumper user on most S550s with 17-19" wheels. The part I found to be correct for the GT350R is FR3Z-8321-B, but the post I just found here on M6G says that is for S550s with 20" wheels and the GT350, non-R. That post lists FR3Z-8321-C for the GT350R.

Don't compare mfg p/n to service p/n, they're not even the same base part half the time (the middle bit).

My advice is use the bumpers that came with the dampers. Trim the rears about 0.5" to get some more travel before contact, as the S550 does this.

 

[Dave TBG]

Don't compare mfg p/n to service p/n, they're not even the same base part half the time (the middle bit).

My advice is use the bumpers that came with the dampers. Trim the rears about 0.5" to get some more travel before contact, as the S550 does this.

Thanks, I just assembled the struts and used the dampers that came with them, as shown in the picture they are a bit shorter and the material seems very similar. The backs are even more different, the ones that came with the shocks are, at most, 2" long the other ones are almost twice as long. I haven't taken them apart yet.

It looks like I may have forgotten to order the rear upper spring isolators. Any idea if I can reuse the existing parts?

 

[BmacIL]

Thanks, I just assembled the struts and used the dampers that came with them, as shown in the picture they are a bit shorter and the material seems very similar. The backs are even more different, the ones that came with the shocks are, at most, 2" long the other ones are almost twice as long. I haven't taken them apart yet.

It looks like I may have forgotten to order the rear upper spring isolators. Any idea if I can reuse the existing parts?

Yeah no problem. They're just to prevent noise.

 

[Dave TBG]

Thanks again. With the wide range of part numbers for some of these things I'd assumed that they were fitted to very specific applications, e.g. different springs with different wire diameters might have an isolator that fit just that wire diameter. Apparently, this isn't the case as many of these parts fit a wide range of vehicles and usually overlap quite a bit. I'm starting to think someone's bonus depends on creating more numbers.

 

[BmacIL]

Thanks again. With the wide range of part numbers for some of these things I'd assumed that they were fitted to very specific applications, e.g. different springs with different wire diameters might have an isolator that fit just that wire diameter. Apparently, this isn't the case as many of these parts fit a wide range of vehicles and usually overlap quite a bit. I'm starting to think someone's bonus depends on creating more numbers.

Yeah there's a big range of parts that fit but are different. The 20" wheel cars got some different h/w because their wheels are so heavy. GT350s got more because Ford Performance wanted to.

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