Swapping to 9 inch?

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Swapping to 9 inch?

January 17, 2018, 09:05:48 AM

I just picked up this 86 Turbo Coupe, its really in great shape, still has the motor, auto trans, intact interior.
Plan is a father and two daughters race project, turn it into either a street/strip or strip only grudge test and tune car s...and later full on Drag car.
Also toying with a drag week project..too many options. Regardless the rear will need to be solid.

I have a lot of stuff left over from my 67 Mustang, that I went BBF on. 393 W, carbs, dist, Toploader, 9 inch center sections and axles, disc brake kits etc. I kept this stuff knowing I would build another drag type car.

Soooo, I want to use as much stuff on this build as I have instead of buying stuff. when I went BB on the 67, I started at the rear, and worked my way forward beefing the car up, gonna follow the same logic here.

I am a 67 68 Mustang guy, leaf springs, clutch cars.....never had this Fox stuff before, so I am new to this and out of my comfort zone. I finished my 67 (my 6th Mustang) this past summer; it is a 521 Kaase motor, Jerico DR4, mini tubbed and narrowed 9 inch. The only thing I didn't do was the machine work on the block and balancing, shooting the paint and narrowing the 9 inch housing. I only add this, not to toot, but hopefully quell any comments about experience etc.

I'm wondering should I keep this Triangulated four link set up, I don't want the rear, I want a 9 inch, so build a bolt in housing for this, or shift to a more traditional 4 link coil over set up. Point being, if I am changing rears, go all the way or is the stock triangulated set up with a 9 gonna just as well?

Not sure which way I will go with the motor, using the 393 its gonna be a 351 W base and I have a bunch of parts. I was on the path for a 408 when I shifted to BB. I am pondering carb clutched car, or turboed auto. I will use a tubular K member of some type. (Man, there is a lot of confussing info out there about that.

Thanks in advance for your help and patience.....

Swapping to 9 inch?

Reply #1 – January 17, 2018, 10:03:33 AM

These cars take Fox and SN95 tubular K-members really well with some shims (do a search on here). As for the 9" it will be like stuffing one under a Fox Mustang so nothing changes there. Several companies make the hardware to jig up a 9" to bolt into a Fox body car. I understand your desire to go with a 9" but there are several 10.5W cars our there with 8.8's and supporting some crazy horsepower levels.

I installed an 8.8 out of an 88 Mustang GT under my Bird and it was a bolt in. The one thing you need to realize is that the TC rear ends are virtually identical in width as the SN95 Mustang 8.8's however the Fox Mustang 8.8 rears are about 3/4" shorter per side than a TC 8.8. You can use the 8.8 in the TC and get a 31 spline center section, 31 spline Moser, Strange, or Yukon axles and build a pretty bullet proof 8.8. You cannot use (more like should not) the Mustang UCA's and LCA's as they are the wrong length and will move the rear end forward in the car. Several companies make control arms for these cars:

Maximum Motorsports - LCA's only (fixed length but adjustable spring perches) http://www.maximummotorsports.com/1983-88-Thunderbird-C429.aspx
Griggs Racing - LCA's only and no spring perches (adjustable and meant for coil over setup) http://www.griggsracing.com/index.php?cPath=4332_4316_4375
Global West - LCA's and UCA's (ask them for the GM "A" Body UCA's for a Thunderbird and they make fixed and adjustable) http://www.globalwest.net/1980-88thunderbird.html
CHE - UCA's and LCA's (fixed and adjustable) https://www.cheperformance.com/collections/83-88-thunderbird-and-cougar-parts

So the weak point on the 8.8's are the C-clips that hold the axles in but you can get a kit that modifies the 8.8 housing to accept 9" axle housing ends thus eliminating the need for the C-clips. Google is your friend here and Mark Williams had a good article on this: http://www.markwilliams.com/beefup.aspx

If you decided to run a true four link with a Z or panhard bar then any advantage of using the 8.8 other than you already have it is moot. There are several kits out there that four link a Fox Body car that will work in the Birds and Cougars.

Swapping to 9 inch?

Reply #2 – January 17, 2018, 10:54:46 AM

Thanks much, greatly appreciate it...good looking bird and stang. I'm leaning towards the nine as my ultimate goal, and always my initial plan was pull the 521 out of the Mustang, turn it back into more street/cruise car and the bird into a pure track car....so maybe even going the back half route on that, do it once the first time and not do it twice...learned that from the 67 rear end.

You have a tubular in your 85 or stock type? Only reason I am leaning towards tubular, weight and what I have heard, less headache with fit and steering components.

thanks again.

Swapping to 9 inch?

Reply #3 – January 17, 2018, 09:34:43 PM

T-Bird is a complete Griggs Racing front suspension (sans the Maximum Motorsports CC plates) for a Fox Mustang and the rear has Griggs LCA's, Global West UCA's and Griggs coil overs in the rear. The Mustang is a full Maximum Motorsports car with Griggs coil overs on all four corners complete with the ABS from an 1995 Mustang GT. I opted for the SN95 width 8.8 in the Mustang behind the 331 and T5. Bird has a 351W with a NX Shark fogger and a Tremec TKO.

Swapping to 9 inch?

Reply #4 – January 17, 2018, 11:41:54 PM

i was at one time pondering swapping in a 9" into my 87 T, due to the fact I have had plenty of experience with them, but after doing a little research, an 8.8 is fine for my needs. I dont know if i'm really pushing my car as hard as you are planning on pushing yours tho.

regardless, I can't wait to see this build happen!

Swapping to 9 inch?

Reply #5 – January 18, 2018, 08:59:51 AM

If you are dead set on the 9" which here is a Fox housing 9" on ebay and they will do custom lengths. Price did not seem bad for it being jigged up and having the correct LCA and UCA connection points on it.

https://www.ebay.com/itm/9-Ford-Fox-Body-Mustang-Axle-Housing-9-Inch-Rearend-/221874089797?_trksid=p2385738.m4383.l4275.c10

If you want disc brakes the Explorer brakes will work with Torino style tube ends. Do a search as they are basically a bolt on.

Swapping to 9 inch?

Reply #6 – January 18, 2018, 12:31:22 PM

Beautiful work, not sure on the trans, I am a clutch guy so interested in going to a stick down the road.