Progress Thread My Kenne Bell Twin Screw'd Foxbody thread, (new addition to the family)

Replacing the booster is a headache, and does suck... but might not be necessary. IF you get the old MC off there and find any leakage or corrosion just replace it. If the car was a 4 banger swap, put in the larger one.
 
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I've got the 93 cobra cylinder, and have ran it with both the stock 89 and cobra booster. The 89 booster makes for a VERY stiff pedal, the cobra makes it pretty close to how it felt stock.
 
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Try it first, see if you like it. If not, change the booster.

The booster will add assist. How much you need all depends on the level of brake input you'd like to give. I personally advocate duplicating the factory setup as best as you can (which does involve the booster swap), however some people just do not want to mess with boosters, and I don't blame them. 2 hours of my life I wish I had back
 
This is how I ran my lines with those pieces.

6b9511a06953886c4f8e22390796c70d.jpg


Dammit. Your pic makes me want to rip out my undercarriage and do this.

I did POR15 on my underside, but I didn't go into this level of detail.
 
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Been calling around to some local hot rod shops in my area for a gear install and trac lock rebuild. Getting real tired real quick of people acting like i'm soliciting prostitution or speaking a different language!! You'd think it'd be easy to find a shop that would be willing to take this job and get some easy money. The Diff is already removed and can be carried in by hand, what's the f'ing problem? Take my money!

Question is, are you guys willing to walk me through my first ever differential re-gear and trac lok install?
 
As long as you have the tools (indicator, mag base, and an in/lb torque wrench) it's actually a decently simple job. Trickiest part is getting pinion pre-load right (hence the need for the in/lb wrench). Getting the carrier bearings off is also a pita, but there's usually no huge need to change them.
 
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As long as you have the tools (indicator, mag base, and an in/lb torque wrench) it's actually a decently simple job. Trickiest part is getting pinion pre-load right (hence the need for the in/lb wrench). Getting the carrier bearings off is also a pita, but there's usually no huge need to change them.
I finally got a quote from a reputable shop and I nearly choked when I heard the estimate, $1256.50!! :eek: This is for a new 3.73 ring and pinion, new bearings, seals and rebuild trac lok, etc. WTF? I can do this myself, purchase a HF press, gauges, and perform this gear change 3x and still be under that quote. :nonono:

LMR has their rebuild kit for about $250, new track lok for another $100. Seems like this is the way to go if I can't find somebody reasonable.
 
I finally got a quote from a reputable shop and I nearly choked when I heard the estimate, $1256.50!! :eek: This is for a new 3.73 ring and pinion, new bearings, seals and rebuild trac lok, etc. WTF? I can do this myself, purchase a HF press, gauges, and perform this gear change 3x and still be under that quote. :nonono:

LMR has their rebuild kit for about $250, new track lok for another $100. Seems like this is the way to go if I can't find somebody reasonable.
Wow! I purchased a frpp 31sp diff,3.73 gears and installation kit,diff cover,moser axles,and had it all installed for just a little bit more than that! Is it a lot more labor intensive due to the cobra irs?
 
Wow! I purchased a frpp 31sp diff,3.73 gears and installation kit,diff cover,moser axles,and had it all installed for just a little bit more than that! Is it a lot more labor intensive due to the cobra irs?
I think I'm getting hosed on the price. I have yet to see a post w/ pictures or video that details the Cobra IRS gear install. From what I've read so far the only difference between the IRS and SRA is you need a case spreader to get correct preload for the IRS. The reason behind it is that the IRS diff is aluminum and expands more that an iron SRA so you need to set preload with the aluminum case "expanded" a certain amount to mimic a heated environment. Other than that it's the exact same as your typical SRA 8.8 rear end.

@bird_dog0347 @RacEoHolic330 @90sickfox do you guys have anything to add to this?
 
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I think I'm getting hosed on the price. I have yet to see a post w/ pictures or video that details the Cobra IRS gear install. From what I've read so far the only difference between the IRS and SRA is you need a case spreader to get correct preload for the IRS. The reason behind it is that the IRS diff is aluminum and expands more that an iron SRA so you need to set preload with the aluminum case "expanded" a certain amount to mimic a heated environment. Other than that it's the exact same as your typical SRA 8.8 rear end.

@bird_dog0347 @RacEoHolic330 @90sickfox do you guys have anything to add to this?
I have done one ( my own) swapped to 373. Didn't use a case spreader and didn't have any problems either. I could have just been lucky. I've done a lot of ford rears and I set this one up just like any other 8.8... I did set it without the ring gear installed. Its not difficult. If you were here in Maryland you'd have to order me a needed part for my car and I'd help you out. Nothing big....let's say a set of crystal clear 6 piece headlights [emoji106] or...around 150- 200 bucks... Lol. Don't let them get over on you man. Sounds like they're just scared to touch it.
 
I have done one ( my own) swapped to 373. Didn't use a case spreader and didn't have any problems either. I could have just been lucky. I've done a lot of ford rears and I set this one up just like any other 8.8... I did set it without the ring gear installed. Its not difficult. If you were here in Maryland you'd have to order me a needed part for my car and I'd help you out. Nothing big....let's say a set of crystal clear 6 piece headlights [emoji106] or...around 150- 200 bucks... Lol. Don't let them get over on you man. Sounds like they're just scared to touch it.
Thanks for that offer! Too bad I'm so far away up in the Pacific Northwest though. I did however find a helpful website forum post after some creative searching and got what I was looking for.

Hopefully I can link another stang site for others to see.
http://www.svtperformance.com/forum...50-Homemade-case-spreader-and-holding-fixture

If not then here is a pic, compliments go to "wjurls" on the SVT site
diff spreader.jpg


You are supposed to spread the case 0.030" and then shim the carrier and check back lash. I've read that a lot of people (as well as @90sickfox )have had success without doing this. :shrug::scratch:
 
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That's a neat little jig... I'd like to see results before and after spreading to see how much of a difference it makes.
 
:chin Hmm, fuel pump access door? @bird_dog0347

fuel pump access door.jpg
Ummm, wut? lol... Did you install that or it was already under the trunk carpet?

I think I'm getting hosed on the price. I have yet to see a post w/ pictures or video that details the Cobra IRS gear install. From what I've read so far the only difference between the IRS and SRA is you need a case spreader to get correct preload for the IRS. The reason behind it is that the IRS diff is aluminum and expands more that an iron SRA so you need to set preload with the aluminum case "expanded" a certain amount to mimic a heated environment. Other than that it's the exact same as your typical SRA 8.8 rear end.

@bird_dog0347 @RacEoHolic330 @90sickfox do you guys have anything to add to this?

My gears were also done with the carrier out of the car and it was $150 for the labor, and they didn't have to spread the carrier like that. No problems with my gears whatsoever, just like any normal 8.8 gear install once it is out of the subframe.
 
Ummm, wut? lol... Did you install that or it was already under the trunk carpet?



My gears were also done with the carrier out of the car and it was $150 for the labor, and they didn't have to spread the carrier like that. No problems with my gears whatsoever, just like any normal 8.8 gear install once it is out of the subframe.
That trunk floor cut out was what another person did to gain access to their fuel pump when it failed after their IRS swap.

The guy that quoted me the huge price said his quote had 8hrs for labor in it. From what I've seen in the past with contractors is if they are quoting a job that they don't want they throw a huge estimate at it.
 
8 hours maybe for a novice doing this on their back. With the pumpkin already out and all necessary tools and parts (assuming Ford gears where you can usually reuse the same thickness pinion shim), maybe about two hours for a guy who does these things on a semi-regular basis. There's really not much to them, just have to mock up the backlash/mesh a couple times, and like I mentioned earlier getting the pinion pre-load right can be tricky.
 
You'll need to use at least one crush sleeve to set it up and then have the spacer cut to the crushed length. Definitely doable, and not a bad idea, but makes more sense if you know you're going to be tearing it apart again (which with how often the pinion seal leaks on the 8.8s could be worth it).
 
I had a local trans shop do my gear swap for $150. They installed the 3.27s and set everything up for me. The nice part about the IRS is that you can just drop off the pumpkin. You don't have to cart around an entire rear end.