SPC adjustable upper control arms

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SPACECOWBOY

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I am going to update my upper arms and want to go with SPC but the only have them for 1973 and up. Does anyoneknow the difference between 1967,68,69 and the newer ones? I am assuming disk brakes l have Areospace drag race disks up front.
I see some folks on hear have used them just checking before I order.
 
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Size of the ball joint taper. Like all of the 73+ UCA's the SPC arms use the large ball joint. You need to run a 73+ or FMJ spindle.

What spindles do you have on the car now?
 
Size of the ball joint taper. Like all of the 73+ UCA's the SPC arms use the large ball joint. You need to run a 73+ or FMJ spindle.

What spindles do you have on the car now?

Pre 73 spindles with aerospace drag disks ,do they sell big to small ball joints or should I just ream them out?
 
You'd have to ream the spindles for the larger taper.

I know QA1 makes a small ball joint tubular arm, but I don't think the SPC does. You might ask Peter Bergman, aka @GMachineDartGT, he sells the SPC arms.
 
Did you ever get those spindles reamed? The machine shop would have to have a piece with the same taper as the bigger ball joint I assume.

I emailed SPC today asking about changing the ball joint on the arm to the smaller pre 72 one but got this answer:

"Looking back at a bunch of old catalogs, I could not find any older A-Body arms. I asked an engineer familiar with these arms about it and the quote is “the narrowness of the OE arms compared to the later cars leads to strength concerns and the angle of the ball joint plate is not optimal.” So, SPC cannot help you for the older Dart. We only have the one size upper ball joint plate which fits the K772 Moog equivalent joints used in the later A-Bodies and the 1962-74 B- and E-Bodies. I don’t believe this plate will accept the smaller joint but I do not have one to check or have access to the dimensions. If you need any dimensions from our parts, please contact me."

Are the arms different length with different "plate angles" before and after 1972? I assumed the only difference was the diameter of the hole for the ball joint?


Edit: Just read on Magnumforce website that their large ball joint upper control arms can be used on older cars if the spindle is "drilled out" so not sure what is true.
 
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Did you ever get those spindles reamed? The machine shop would have to have a piece with the same taper as the bigger ball joint I assume.

I emailed SPC today asking about changing the ball joint on the arm to the smaller pre 72 one but got this answer:

"Looking back at a bunch of old catalogs, I could not find any older A-Body arms. I asked an engineer familiar with these arms about it and the quote is “the narrowness of the OE arms compared to the later cars leads to strength concerns and the angle of the ball joint plate is not optimal.” So, SPC cannot help you for the older Dart. We only have the one size upper ball joint plate which fits the K772 Moog equivalent joints used in the later A-Bodies and the 1962-74 B- and E-Bodies. I don’t believe this plate will accept the smaller joint but I do not have one to check or have access to the dimensions. If you need any dimensions from our parts, please contact me."

Are the arms different length with different "plate angles" before and after 1972? I assumed the only difference was the diameter of the hole for the ball joint?


Edit: Just read on Magnumforce website that their large ball joint upper control arms can be used on older cars if the spindle is "drilled out" so not sure what is true.

SPC is clueless. They didn’t design them so there is nobody to ask...
 
HDK sells small ball-joint pre 72 adjustable chromoly UCA assemblies.........$298 plus shipping. They came standard with street friendly adjustable poly-ends but you can upgrade to heims (non street / drag pack ) for an additional $50.

Presently, they are not shown separately, just with the coil over only package

HDK Single lower control arm torsion bar eliminator kit
 
HDK sells small ball-joint pre 72 adjustable chromoly UCA assemblies.........$298 plus shipping. They came standard with street friendly adjustable poly-ends but you can upgrade to heims (non street / drag pack ) for an additional $50.

Presently, they are not shown separately, just with the coil over only package

HDK Single lower control arm torsion bar eliminator kit


These look really nice and the price is great so I would consider getting them instead.
My only question is should the piece that holds the ball joint not be at an angle? It is at an angle on the original arms as well as Hotchkis and a few others to compensate for the overall arm being slanted backward in the car. Then there are other aftermarket arms that are just like these HDK ones as well.

part7.jpg
 
I reamed them with a reamer from speedway . Not a big deal really.

Did you just do this with a hand held drill and test fit the new big ball joint until you were happy?

I read in a different tread where autoxcuda said this will not weaken the spindles enough to worry about it and that the ball joint stud will break first anyways so that is good.

It also seems that the SPC comment about the "narrowness" of the old arms and plate angles is wrong, after reaming they must be a perfect fit.
 
These look really nice and the price is great so I would consider getting them instead.
My only question is should the piece that holds the ball joint not be at an angle? It is at an angle on the original arms as well as Hotchkis and a few others to compensate for the overall arm being slanted backward in the car. Then there are other aftermarket arms that are just like these HDK ones as well.

View attachment 1715400839

I have not seen an A-body UCA yet that was totally flat like that at the ball joint. Not sure how that would work out with your caster settings at all.

The other thing about those UCA's is their wide " U " shape. If you intend to run a wide front wheel, like 8" or more, they won't work. I had a set of UCA's similar to those and with an 18x9" and 6" of backspace the rims hit the UCA's at full steering lock, the "U" shape makes them wider than the original arms near the ball joint. So if you're planning a "pro-touring" style car with wide front tires they're not a good choice, you'd want a UCA with a tighter " V " shape.
 
If you guys want regular tubular arms, no SPC, the QA1s are the nicest.
1. Only one with droop bump stop
2. Greasable bushing not a heim
3. Very beefy around the ball joint
4. Fits easily with high offset wheels
5. Torture tested by me at the track and streets . PM if anyone would like a pair.
 
If you guys want regular tubular arms, no SPC, the QA1s are the nicest.
1. Only one with droop bump stop
2. Greasable bushing not a heim
3. Very beefy around the ball joint
4. Fits easily with high offset wheels
5. Torture tested by me at the track and streets . PM if anyone would like a pair.

And they make a pair with the small ball joint too don’t they?
 
for those wondering about the U shape....... HDK UCAs are purpose built in the U shape to clear a 3.5" od coil spring ....if the UCAs work for other applications, great, but are NOT marketed as a factory replacement.....I recommend the Qa1 arms for that. Additionally, HDK includes adjustable bump stops with all HDK chromoly upper arms and part of constantly attempting to improve our products, ALL HDK chromoly UCAs are now shipped with angled ball joint receivers for improved movement.

The fact that the HDK coil over only UCAs fill the void for someone wanting small ball joint, adjustable UCAs with poly or heim ends is a plus (to some)
 
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Did you just do this with a hand held drill and test fit the new big ball joint until you were happy?

I read in a different tread where autoxcuda said this will not weaken the spindles enough to worry about it and that the ball joint stud will break first anyways so that is good.

It also seems that the SPC comment about the "narrowness" of the old arms and plate angles is wrong, after reaming they must be a perfect fit.

I used a drill press and a new ball joint and fit till happy.
 
I used a drill press and a new ball joint and fit till happy.

Do you have a part # or source for the reamer you bought? I use FMJ or 73+ spindles on all of my cars but it might come in handy for someone else trying to run aftermarket UCA's on the SBJ spindles
 
Do you have a part # or source for the reamer you bought? I use FMJ or 73+ spindles on all of my cars but it might come in handy for someone else trying to run aftermarket UCA's on the SBJ spindles

I do ill fetch it for you tomorrow.
 
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