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

[FoxMustangLvr]

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.

I'm taking a chance on one more person for a quote. He's a guy that the local Mustang club referred me to. If this doesn't work out then I'll just do a fluid change on the differential and put the gear change off till the Summer as I gather more tools and funds for the job. I'd like to buy a HF press, they get good reviews for the DIY home mechanic type. Having that press would've worked wonders for the IRS bushing rebuild.

 

[FoxMustangLvr]

A little progress over the weekend.

I decided to use the factory holes in the frame rail from the quad shock mounts. I added some 3/16" mild steel to the IRS brackets, welded the old hole closed and drilled a new hole to match up the stock Fox locations.

All finished up along with the brackets that will drop in from the holes I cut in the hatchback floor. I used 3/16" steel, 1.5"x6" with 1.5" grade 8 bolts.

Brackets installed

I ended up having to remove my gas tank in order to drill the passenger side frame for the vertical bolts. The corner of the gas tank is in the way of drilling from the underneath of the car. I didn't want to remove my interior quarter panels to drill from above and besides I needed to remove and clean up the gas tank and replace the seals anyway.

 

[Black1987]

Did you weld the plate in with the mounting bolts or is it thick enough not to allow a moment on it? Do have a pic of the access hole you cut?

 

[FoxMustangLvr]

Did you weld the plate in with the mounting bolts or is it thick enough not to allow a moment on it? Do have a pic of the access hole you cut?

I did not weld the plate to the frame rail. The plate is plenty thick enough to keep any flexing to a minimum if any at all. I didn't have good enough light to take a picture of the access hole by the time I got it done. I'll try later when I get home if it's still light enough out.

 

[bird_dog0347]

Nice progress, not sure why I never thought to weld it up like that to use the quad shock bolt... good thinking.

 

[FoxMustangLvr]

@bird_dog0347

Did MM give you a recommendation for your rear coil overs or did you just buy them and throw them on without their advice? When I talked to Jack Hidley he recommended doing what your first setup was which is cutting the stock Cobra IRS springs down to desired ride height along with stock Cobra shocks out back. MM did not recommend rear coil overs for me regardless of the fact they know that I'm running them up front. Was there a decent difference when you upgraded the rear?

 

[FoxMustangLvr]

Also, how did you guys install the IRS, just the subframe and then assembled it under the car or did you install it complete?

 

[bird_dog0347]

I told MM all of my goals and Jack suggested all the spring rates for my full C/O kit. He didn't try to talk me out of the rear coil overs, but we might have very different goals. There was a huge difference when I went to C/O all the way around, but I was also really mismatched to begin with. Up front I had Eibach sportline springs with Tokico Blue struts and cut IRS springs in the rear with Bilsteins. Eleventy Billion times better now, stiffer, but still a much better ride.

I installed the subframe front mount points with nothing in it, left the rear hanging, then assembled it that way and swung the rear up into place. I had such a hard time getting the front in I didn't want to screw with it again.

 

[FoxMustangLvr]

I told MM all of my goals and Jack suggested all the spring rates for my full C/O kit. He didn't try to talk me out of the rear coil overs, but we might have very different goals. There was a huge difference when I went to C/O all the way around, but I was also really mismatched to begin with. Up front I had Eibach sportline springs with Tokico Blue struts and cut IRS springs in the rear with Bilsteins. Eleventy Billion times better now, stiffer, but still a much better ride.

I installed the subframe front mount points with nothing in it, left the rear hanging, then assembled it that way and swung the rear up into place. I had such a hard time getting the front in I didn't want to screw with it again.

Just because of budget I'm just going to cut the stock Cobra springs and use the factory Cobra shocks in the rear with my coil overs up front. Right now I'm on the fence with the rear end. I talked to a guy yesterday that quoted me $675 to rebuild the diff. That includes new Yukon gears, bearings, traction lock rebuild, seals and labor. He said also that I could find a good used OEM 3.73 ring and pinion. He has good luck with them not whining. He doesn't like the aftermarket FRPP gear sets at all.

 

[bird_dog0347]

Just because of budget I'm just going to cut the stock Cobra springs and use the factory Cobra shocks in the rear with my coil overs up front. Right now I'm on the fence with the rear end. I talked to a guy yesterday that quoted me $675 to rebuild the diff. That includes new Yukon gears, bearings, traction lock rebuild, seals and labor. He said also that I could find a good used OEM 3.73 ring and pinion. He has good luck with them not whining. He doesn't like the aftermarket FRPP gear sets at all.

Wow man, that's too much! What's wrong with the diff and 3.55's? Don't cut your springs till you get it on the ground and check height, I cut mine 1 coil and it was a bit too low.

 

[FoxMustangLvr]

From what I've read my year IRS came with 3.27's

 

[mikestang63]

I am sure you know this, but replace the gasket for the filler neck on the tank or it will leak and smell to high heaven.

 

[bird_dog0347]

My bad, you must have a 99/01 IRS which did come with those gears. Either way, Don't pay over $150-200 for gears to be installed, and go with new gears for sure. I got the kit from LMR with new bearings, gears, fluids, etc. and there's just no good reason to half ass it or save $50-100 on something that big of a PITA to re-do.

 

[Noobz347]

I always have to think back to WTH is going on in here. I look at the update thingking Why's he doing all this?

 

[FoxMustangLvr]

I always have to think back to WTH is going on in here. I look at the update thingking Why's he doing all this?

Because I can't leave anything alone! Because I can. Because Mod bug!

Truthfully, in search of better ride comfort, stance, and handling.

 

[FoxMustangLvr]

My bad, you must have a 99/01 IRS which did come with those gears. Either way, Don't pay over $150-200 for gears to be installed, and go with new gears for sure. I got the kit from LMR with new bearings, gears, fluids, etc. and there's just no good reason to half ass it or save $50-100 on something that big of a PITA to re-do.

I've pretty much decided I'm going to purchase a press and all the tools and do it my dang self! It will come out to about the same price as what the guy quoted me plus I need/want the tools for other stuff like pressing in 94/95 ball joints into my front control arms so I don't have to ghetto rig it with washers.

 

[bird_dog0347]

I've pretty much decided I'm going to purchase a press and all the tools and do it my dang self! It will come out to about the same price as what the guy quoted me plus I need/want the tools for other stuff like pressing in 94/95 ball joints into my front control arms so I don't have to ghetto rig it with washers.

I do crap like that all the time... I bought a welder cause I wanted cats in my H pipe and SFC's. I paid more in the long run, but now have a tool and a skill.

 

[FoxMustangLvr]

About to do my front end for my 5 lug Cobra swap. Question is how good are the Moog brand ball joints? House brand ball joint with life time warranty are $17 each while Moog are $50+ each. Is it worth the price for Moog?

 

[90sickfox]

Also, how did you guys install the IRS, just the subframe and then assembled it under the car or did you install it complete?

I installed mine complete but, I had a lift at my disposal. That thing is heavy and might be a bear to deal with on the ground. And, yes, Moog is worth it. Moog puts a lot of engineering into their parts.

 

[FoxMustangLvr]

I installed mine complete but, I had a lift at my disposal. That thing is heavy and might be a bear to deal with on the ground. And, yes, Moog is worth it. Moog puts a lot of engineering into their parts.

Thanks, I think I will spend the extra few bucks for the Moog ball joints. I'm working on my back on the floor and I already have the cradle installed at the moment. Fortunately I didn't have to spread my torque boxs with the MM bushings. I will piece it together from here on out as parts are ready. Just waiting on my tax refund (next week) and I'll be able to order all special tools and parts to regear the diff. The entire rear end is just waiting on that and the rear will be done.

It seems like Spring is going to come early. Weather forecast is showing low 50's this next week which is twice as high than normal temps for this time of year. I'm hoping to have this car on the ground early March and driving it on clear days.