North American Turbocoupe Organization



Mustang Adjustable Control Arms on Thunderbird
bang4thebuck Offline
Senior Member
#1
Im looking for some affordable upper and lower control arms for the bird. I found adjustable upper and lowers for 79-04 mustangs from upr. Anyone know if they adjust long enough for the Thunderbirds? CHE has a delay in production for their control arms and the Maxim Motorsports are on the expensive side.
1987 TC 5 speed. To date: AGP 50 trim T3/T4 .63 stage 2 turbo, Ebay bov, 28psi, 255hp pump, Kirban FPR, Ebay Front mount, Full 3 inch Exhaust, Ported Bob's Log, Megasquirt, 55lb. injectors, boport 1.5 cam, boxed lower control arms, Methanol Kit, Ram HD Clutch, front lowered 1/2 inch and E.T. Streets for the track. Best so far 12.5 at 110.8. still tuning.
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Robert Camp Offline
Posting Freak
#2
This topic comes up repeatedly and answer is the same. No. They are different lengths and differ as much as 3/4", either the upper or lower, I can't remember which. I have never seen lowers that are length adjustable anyway.

Sketch out the geometry and consider that the angle of the upper differential mounts are fixed. Depending on the length of the upper arm, the distance between chassis mounts have to be different, longer arms the chassis mounts are further apart. Attempting to use shorter arms will result in the arms not being perpendicular to the mounting bolts.

I have seen an article on the web where someone actually claims they bolt up. The author does not report how they affected the handling of the car.
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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bang4thebuck Offline
Senior Member
#3
I was hoping the adjustment threads would be long enough to make the length correct. I just read on Turboford that the uppers are over an inch longer than the mustang units. The lowers are only 1/2 shorter than thunderbird units and I would think you could thread them out to achieve the correct length with the adjustable lowers seen here http://cgi.ebay.com/ebaymotors/ws/eBayIS..._500wt_956
1987 TC 5 speed. To date: AGP 50 trim T3/T4 .63 stage 2 turbo, Ebay bov, 28psi, 255hp pump, Kirban FPR, Ebay Front mount, Full 3 inch Exhaust, Ported Bob's Log, Megasquirt, 55lb. injectors, boport 1.5 cam, boxed lower control arms, Methanol Kit, Ram HD Clutch, front lowered 1/2 inch and E.T. Streets for the track. Best so far 12.5 at 110.8. still tuning.
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50RACER Offline
Senior Member
#4
Here is good article about it.
http://www.fordmuscleforums.com/suspensi...check.html
87 TC Medium Canyon Red
88 TC Black Beauty
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Robert Camp Offline
Posting Freak
#5
Those are the first length adjustable lowers I've seen. Are those spring perches the same distance from the front mounts as standard TC? If it's shorter then the height of the rear end is going to change and so is the wheel rate of the springs. Lengthening the back mount changes the location of the sway bar mounts, is the sway bar going to mount up? As the stated purpose of the adjustment is thrust alignment (not specifically stated but that's what is meant) and pinion angle, both of which generally don't require much adjustment length, is there enough to make up 1/2". If you lengthen the lowers the uppers have to be lengthened to maintain pinion angle.

It's up to you, if you don't value handling above straight line performance, it may well work just fine. But the geometry issues don't change unless you make up the difference in length on uppers and lowers and all other important mounting locations are maintained. Don't be surprised if you experience other issues.
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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Chuck W Offline
Posting Freak
#6
As I mentioned on TF, IIRC the extra length on the TBird RLCAs is in front of the spring perch.

We were making the adjustable lowers at KB's over 10 years ago. Still have an early set on the '83.
83 TC Clone, 85 Mercury LTS, 97 Volvo 850 T5 Turbo, 78 Volvo 240, 93 F150
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Robert Camp Offline
Posting Freak
#7
Quote:Originally posted by 50RACER:
Here is good article about it.
http://www.fordmuscleforums.com/suspensi...check.html
That's the article I was referring to in my post. But I don't think much of that article. First, his measurement of the lower difference is less than several others have reported. That aside, shortening the lowers requires shortening the uppers to maintain pinion angle. The uppers are at a fairly steep angle and even 1/4" shortening will induce immediate bind, especially with urethane isolators. In the article he says he uses TC uppers, but then has to adjust pinion angle, i.e., shorten the uppers. If you would spend the time to draw a couple geometric diagrams, they don't even have to be to scale, you'll see the problems that occur immediately.

Chuck, the adjustable lowers show in the link are adjustable at the rear and have spring perches for the Mustang. That would move the spring perches forward relative to the TC perches.
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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Chuck W Offline
Posting Freak
#8
The UPR Mustang lowers the OP was looking at in the ebay link have the adjustment at the front. The spring perch is at the rear of the RLCA.

I never said, run the rear control arms at Mustang length in a Tbird, I said IF there was enough adjustment to safely adjust them to the PROPER (TBird)length, they would be fine. However, most Mustang RUCA do not have enough adjustment built in to safely cover the 1-1/8" difference.
83 TC Clone, 85 Mercury LTS, 97 Volvo 850 T5 Turbo, 78 Volvo 240, 93 F150
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Robert Camp Offline
Posting Freak
#9
Yep, I screwed up on identifying front and rear. And I never said you said......
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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50RACER Offline
Senior Member
#10
I just bought a set NOS Southside Machine lower real control arms that were listed as being for a fox Mustang. The Center to Center bolt hole measurement is 17 3/4 in. on the Southsides, the same as my 87 TC stock units. UMI Performance sells copies of the Southsides for $160.00. These are great for a drag race project, but not really recommended for street driving.
http://www.umiperformance.com/catalog/in...ath=11_124
87 TC Medium Canyon Red
88 TC Black Beauty
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