I have a stupid idea

Now hear me out before you tell me how dumb this idea is.

I have a 2005 base 4-banger w/ manual transmission. My original plan for the truck was to 4-link the rear, run coil overs, swap to disc brakes and drop it using the DJM kit. Now I've been thinking about getting all this done in a different way. Swapping in a Mustang IRS.

The bolt pattern for both hubs is the same, with a larger center bore, axle width is within a couple inches of each other and one variation of the Mustang differential has a 3.31 gear ratio just like my stock diff.

Pros:
This gets me disc brakes, without the weakened/no e-brake issue of most of the rear disc kits.

Takes care of the rear drop

Gets me an IRS over the 4-link.

Cons:
The Mustang IRS would have to be welded in, but so would the 4-link.

I would need to figure out where/how to mount some coil overs, but I had already planned on doing this.

The gas tank would have to be relocated to either the rear in place of the spare or put a fuel cell in the bed.

I would have to have a custom driveshaft made.

Ok, now everyone can pick this apart and point out things I've missed and tell me how dumb it would be.

 

I say go for it. Step 2 after...Turbo

 

If you don't care about putting time and money into a 4cyl 20 year old truck, go for it. I'd like to see the end result. It might be cool.

 

agree

 

Do it

 

Yeah, but this 20 year old truck only has 52,000 miles on it and I put 10K of those miles on it in the last year or so. Also I just modify my vehicles, started at 16 and have keep doing it for almost 40 years. I was sort of hoping someone would point out something big I missed. Looks like I shall have to get the project car up and going so I can daily it while putting this under the welding torch.

 

Nope, if I go forced induction I would go supercharger. But it Cali emissions would prevent that. Sort of hard to get that to pass the visual portion of the test.

 

It's not crazy at all.
People like you, are the ones that get things done.
Other never do, because it's not "drop-in" or easy.

Go for it.

I'd be interested to see the put come.

 

I like it.

Not a Mustang IRS but a Tacoma
https://youtu.be/oCIwLO5nvd8?si=xuK5y6NlnWO-gp5o

Not a Tacoma but a Mustang IRS
https://youtube.com/shorts/GGB-wuBtu5A?si=DfD_mFJr0PyWYVJX

 

Yeah, I've watched both of those videos. There are some much better ones, especially in the F100 crowd, on doing it but those at least give some ideas.

 

Do it

 

Only thing I can think of is to maybe try and get a body cut when you get the rear suspension setup? thinking of the floor pan thru fenders, basically a cross section slice of the car that contains the upper shock/coilover mounts, that way you'd have a template to work off of for
the truck side upper mounts.

Does that make any sense?

 

While I can see where that might work I'm going to dump the stock shock and spring setup and just go with a custom coil over that is the correctly length once I put the rear in. It's just easier and won't require cutting into the bed to fit it.

 

makes sense to me, and sounds like a fun and unique way of doing it in general, dig the swap plan.

Look forward to pictures and problem solving when the time comes


Edit: replaced a question about mounts with a link to mounts, lol

 

These guys are way down the rabbit hole

https://team321.com/irs-assembly/mustang-irs-mounting-kit/

 

Yep, looked over their kit and while it would be nice to get something almost ready made I'll need to cut into the frame since I want to go lower than their brackets would let me.

 

I say go for it.

I admire your can-do attitude. if you can afford it, do it.

 

Already been done.
There was a guy with a stunner who didn’t an IS300 it’s swap. My buddy did an s13 swap in his pick up. Not a crazy idea. It’s been done. Good luck I’m sure you will have lots of options.

 

Doesnt look like theres too much to the kit anyways, pretty sure fabbing four flat spots for bolts will be the least of it, lol. And from the sound of it you obviously have a plan and the skills to make it happen


Pretty clear from the polls that we all agree its a great idea, so start throwing money at it and take some pics so we can all support your progress!!!