Offset upper control arm shafts
Race Director
Joined: Nov 2006
Posts: 13,238
Likes: 7,829
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
I'm running Moog offset shafts. Which we also slotted for more caster. Good inexpensive mod.
Drifting
Joined: Jun 2025
Posts: 1,716
Likes: 597
slugs are common in oval track racing chassis. They fit into elongated/slotted holes and have a bolt hole located in several specs.
check either
Port City Chassis at Muskegon MI or
Port City Race Cars at Mooresville NC or
Circle Track Supply at Statesville NC
check either
Port City Chassis at Muskegon MI or
Port City Race Cars at Mooresville NC or
Circle Track Supply at Statesville NC
Last edited by Rebelyell; Feb 26, 2026 at 07:31 PM.
Drifting
Joined: Aug 2019
Posts: 1,510
Likes: 498
I'm running Moog off set shafts but they are discontinued, I bought a new set for my black 1980 and by the time I wanted to order a set for my white 1980 they were discontinued but was able to get a set of used Moog offset shafts from Van Steel so it's good to know you can still get them new
Race Director
Joined: Mar 2017
Posts: 11,949
Likes: 4,507
From: Virginia
Since it is a bit of a chore to find the part numbers, and even their website is kinda vague, I'll post the links here.
SPC Performance makes adjustable UCAs for our cars. I have two sets of the "race" version (which has delrin bushings that must be lubed periodically). Street price is about $600- for the pair, from Summit, Amazon, eBay, or wherever you can get a part number match.
They bolt right on, and you don't have to rebuild anything. I was able to get 6 degrees of caster in my 80.
Race style, SPC 92740
https://www.spcalignment.com/product/92740
Street style, SPC 84360
https://www.spcalignment.com/product/94360
SPC Performance makes adjustable UCAs for our cars. I have two sets of the "race" version (which has delrin bushings that must be lubed periodically). Street price is about $600- for the pair, from Summit, Amazon, eBay, or wherever you can get a part number match.
They bolt right on, and you don't have to rebuild anything. I was able to get 6 degrees of caster in my 80.
Race style, SPC 92740
https://www.spcalignment.com/product/92740
Street style, SPC 84360
https://www.spcalignment.com/product/94360
Race Director
Joined: Nov 2006
Posts: 13,238
Likes: 7,829
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
That's what we're talking about here. HUGE difference in cost between all new A arms and offset shafts.
Same results.
Us poor people and or just thrifty people really like saving over 500 dollars.
Same results.
Us poor people and or just thrifty people really like saving over 500 dollars.
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Race Director
Joined: Mar 2017
Posts: 11,949
Likes: 4,507
From: Virginia
Offset arms from Zip, $80- each.
https://www.zip-corvette.com/63-82-u...et-design.html
Energy Suspension front control arm bushing set (Amazon Links)
Red 3.3108R or Black 3.3108G $80-
The tool to install the bushings
Powerbuilt UCA Bushing Service tool, 648604 $90-
So perhaps a $300- savings over the (adjustable) SPC solution. A bit more if you use rubber bushings. But you'll still need to use shims.
Here's a video showing how to do it.
Race Director
Joined: Nov 2006
Posts: 13,238
Likes: 7,829
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
I didn't watch the video. I never do. I didn't know I had to buy a special tool. I've done my control arm bushings twice now over the years. Didn't purchase anything special.
New bushings , well yes of course.
Zip Corvette is the place to purchase control arm shafts? I'm thinking one can do better price wise.
And yes, even if you only saved 300 dollars, thats 300 dollars I can use to buy food! I'm big on eating.
New bushings , well yes of course.
Zip Corvette is the place to purchase control arm shafts? I'm thinking one can do better price wise.
And yes, even if you only saved 300 dollars, thats 300 dollars I can use to buy food! I'm big on eating.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
Well, if you're going to insist on saving the OP some money...
Offset arms from Zip, $80- each.
https://www.zip-corvette.com/63-82-u...et-design.html
Energy Suspension front control arm bushing set (Amazon Links)
Red 3.3108R or Black 3.3108G $80-
The tool to install the bushings
Powerbuilt UCA Bushing Service tool, 648604 $90-
So perhaps a $300- savings over the (adjustable) SPC solution. A bit more if you use rubber bushings. But you'll still need to use shims.
Here's a video showing how to do it.
https://www.youtube.com/watch?v=Qw7dkZUQa58
Offset arms from Zip, $80- each.
https://www.zip-corvette.com/63-82-u...et-design.html
Energy Suspension front control arm bushing set (Amazon Links)
Red 3.3108R or Black 3.3108G $80-
The tool to install the bushings
Powerbuilt UCA Bushing Service tool, 648604 $90-
So perhaps a $300- savings over the (adjustable) SPC solution. A bit more if you use rubber bushings. But you'll still need to use shims.
Here's a video showing how to do it.
https://www.youtube.com/watch?v=Qw7dkZUQa58
Last edited by stingr69; Mar 15, 2026 at 05:48 PM.
Thread Starter
Instructor
Joined: Dec 2011
Posts: 197
Likes: 27
From: New Jersey
I purchased the Global West ones and since I want to replace the ball joints I figured to do everything and make a complete set to just swap out when I’m ready..
Global West shafts
Moog Ball Joints and Rubber Bushings
2 New to me “after I clean and paint “upper control arms from (CorvetteBen) for $30 each
Global West shafts
Moog Ball Joints and Rubber Bushings
2 New to me “after I clean and paint “upper control arms from (CorvetteBen) for $30 each
Thread Starter
Instructor
Joined: Dec 2011
Posts: 197
Likes: 27
From: New Jersey
Now that I have the offset shafts, does anyone think I should get them slotted because I guess I jumped the gun on my purchase. I really don’t have a problem with camber. I just don’t know if I can get the amount of caster with the shims. How much do I slot them? What’s a good positive caster? I saw 6 degrees caster posted somewhere.
Thread Starter
Instructor
Joined: Dec 2011
Posts: 197
Likes: 27
From: New Jersey
Now that I have the offset shafts, does anyone think I should get them slotted because I guess I jumped the gun on my purchase. I really don’t have a problem with camber. I just don’t know if I can get the amount of caster with the shims. How much do I slot them? What’s a good positive caster? I saw 6 degrees caster posted somewhere.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
JMO - Start off by seeing where you are first.
First, set camber at zero. Then, see how much caster you can get while still holding camber in check. Move the shims from the front spot to the back spot to max out both drivers side and passenger side for caster while holding camber at zero. Move the whole stack if you can, but the camber needs to stay at zero. Camber moves the wheel in-out by adding or subtracting 2 equal thickness shims at the same time on the one shaft. One front shim one back shim - to maintain camber. The limit is when you have zero shims in the forward position but still have zero camber. Then reduce the caster for the higher caster side so it matches the other lower caster side that is already at max. This is pulling a shim out of the high stack and reinstalling it at the lower stack until you are equal caster on both left and right sides of the car. Adjust camber as required with equal shims (add or subtract, if any left) Now you should have caster maxed out for what you have available and camber set to zero. Double check the settings and tighten the fasteners.
Set the toe and drive it.
The modified arms cut slots will allow even more caster, but try it with the existing holes first to see if that is good enough for you is my advice.
First, set camber at zero. Then, see how much caster you can get while still holding camber in check. Move the shims from the front spot to the back spot to max out both drivers side and passenger side for caster while holding camber at zero. Move the whole stack if you can, but the camber needs to stay at zero. Camber moves the wheel in-out by adding or subtracting 2 equal thickness shims at the same time on the one shaft. One front shim one back shim - to maintain camber. The limit is when you have zero shims in the forward position but still have zero camber. Then reduce the caster for the higher caster side so it matches the other lower caster side that is already at max. This is pulling a shim out of the high stack and reinstalling it at the lower stack until you are equal caster on both left and right sides of the car. Adjust camber as required with equal shims (add or subtract, if any left) Now you should have caster maxed out for what you have available and camber set to zero. Double check the settings and tighten the fasteners.
Set the toe and drive it.
The modified arms cut slots will allow even more caster, but try it with the existing holes first to see if that is good enough for you is my advice.