Ugly Horse: 1989 Ford Mustang 2.3T IRS project

1989 Ford Mustang by LeftofLucky

Well, this got out of hand quickly.

That there is a 1989 Ford Mustang LX with the much coveted Secretary Package. NA 2.3 four cylinder, four-speed automatic. I purchased the car from my father for the lofty sum of $400 with the intent of converting it into a beater mountain carver/track rat. Why $400? The car hadn't moved with any regularity since '03, lost its side glass in '05 and had been Casa del Gato ever since. A small ecosystem had blossomed indoors, with everything from small trees growing in the back floorboard to a variety of fungi, rodents, insects and felines calling the cabin home.

The good news was that the car came with a turbo 2.3 out of an '87 T-Bird with a T-5 to match. The original plan was to stick some stiff as hell springs under it, drop the ride height a bit, go with the stickiest tires possible and commence to flogging once the turbo mill and five-speed were tucked safely in the chassis.

Then I bought a set of front brakes from an '03 Mach 1. I get off on brakes like most pony fans get off on displacement. With 13-inches of total rotor diameter and dual-piston calipers, the stoppers were more than any 2.3 will ever be able to overcome. In hind sight, those brakes were the start of a slippery slope.


1989 Ford Mustang, '04 Mustang Cobra IRS by LeftofLucky

The same guy who tossed me the brakes also happened to have an IRS from an '04 Cobra laying around his shop, too. It followed me home. Supposedly the swap is fairly simple, with just a bit of drilling to make everything fit in place. My rear happens to boast 4.10 gears, a limited slip and 10.65-inch ventilated rear discs mashed by single-piston calipers. Win.

As it stands, the car is drivable and legal thanks to a new fuel tank and the associated components, and I've completed the five-speed swap as well.

The only thing stopping the IRS from going to its home is the fact that no one will sell me the inner CV boots, which have commenced to shitting grease everywhere. If anyone knows where to find those pieces, I'm all ears. Stay tuned for more updates.

Zach and I had plans to meet in the middle of the country and race our crap heaps.

Now? NOPE!

That's an awesome project and nice to see it getting a second chance at life! One of the great things about the 4-cyl models is the lack of chassis tweakage due to years of hooning abuse.

Man, Zach, this project exemplifies why you are equal parts insane and awesome. Was the acquisition of the Stang as eventful as your IH truck?

It was damn tempting to roll up, drop in the T5 and head south in the car, but I'm glad I didn't. I pulled it home with the F-250 and a U-Haul float. My subsequent bombing around here in town has resulted in a blown radiator and a deceased alternator, so I'm positive I wouldn't have made it much past Roanoke if I'd attempted the trek.

I don't know if I'm getting smarter, more boring or older. Either way, it was fine seeing the thing in the rearview behind the big V10.

You're making me want to drop a 302 and a Volvo IRS into the 122S. I wonder what that would be like?

Awesome, no doubt.

Naw, I'm actually liking the stock B20. It has charm, and even with the slushbox, it's surprisingly quick ... quick being relative to the speed of molasses at the South Pole.

This thing is already impressive. Five-speed, steelies, and half the usual cylinder count is a recipe for radness ... Can't wait til the boosted mill is ship shape and the rear is in. Also, the paint job (or lack thereof) is so much win right now.

I've heard that an inner C.V. boot for the rear end of a 2002-2010 Explorer will work for that car. Don't know how true it is, the Ford part number is 1L2Z-4L537-AA

Congrats on the getting the motor swap done. Man that IRS looks big and heavy though.

I saw the pic of the suspension and I thought it was some sort of huge opposed twin cylinder aircraft engine.

With that suspension and four cylinder, and especially being a hatch, I imagine you will end up a rearward weight bias??? Should be fun.

When I was in college, I was on my school's Formula SAE team. After not being able to find anything suitable for the duration of the rest of the build, when it was the last thing holding us up from driving, I stitched up 4 CV boots out of innertube rubber. I cut out a pattern (unrolled cone - like a leather shift boot) and stitched it up with some heavy thread, sealed the seam and the stitches with tire patch kit rubber cement, held the ends on the shafts with zip ties.

I wouldn't trust it for 100,000 miles without inspection, but it got our car "on the road" and none of them failed during several autocrosses of practice, competition, and several let's-drive-it-til-something-breaks sessions after competition. They did seep a little around the stitches, they'd always look wet around the edges, but it was a lot better than a torn boot.

And you don't have to remove the shaft to do it.

I'd just clean the joint as much as you can, throw new grease in, throw one over what's left of your old boot, move past it, and put it on the to do list.

It's not like you're going to put the suspension in there and never look at it again. I imagine getting the suspension dialed for canyon carving in (changing spring rates etc.) will involve plenty of more chances to throw a proper boot on while you're in there.

I'm JP and I approve of this build.

This is awesome. I wish you the best!

Neato. Curious why you went with an IRS when the live rear end can be made to handle even better than the IRS with the right combo of parts. Panhard bar/torque arm/3-link or Watt's Link set ups aren't super pricey.