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Rear Sway Bar Installation problems

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Old 03-29-2020, 01:51 PM
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dwalsh7093
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Default Rear Sway Bar Installation problems

My 1977 never had a rear sway bar. I went to install a rear sway bar kit and found that the rear frame is not drilled for the mounting brackets. Even if I were to drill out the holes there would be no way to insert a bolt and hold it for tightening. I thought about a blind nut set up but the investment in a tool and large qty of nuts makes no sense. Also welding a bolt to the frame is not an option as the bracket needs to fit flush to the frame.



wondering if anyone else has run into this problem and what solutions you came up with.
Old 03-29-2020, 02:19 PM
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OMF
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I put a sway bar on my '77 a year or so ago, (never came with one) and I was thinking the same thing.....look a little closer, I found the mounting holes there, along with the nuts pre-installed....they're just covered with a smear of putty to prevent rust damage I'm assuming.

Have another look.....

Ohhh just noticed....welcome to the forum!

Last edited by OMF; 03-29-2020 at 02:21 PM.
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dwalsh7093 (03-29-2020)
Old 03-29-2020, 02:38 PM
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Thank you! Hit the marks with Center punch. And there they are nuts and all!
Old 03-29-2020, 02:52 PM
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jb78L-82
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All 63-82 frames are the same and starting in the late 60's/early 70's all BB C3's came with a factory rear sway bar as well as all SBC C3's with the gymkhana sport/F-41 suspension, no question for a 1977 SBC C3. The holes for the factory rear sway bar have to be in the frame as well as the holes in the trailing arms for the rear sway bar endlinks. There was only one type of trailing arm used as well, no distinction between a Sport suspension C3 and one with the base suspension. Look closer....
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Old 03-29-2020, 02:56 PM
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ignatz
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A word of advice - use the original factory design.
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Old 03-29-2020, 03:10 PM
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jb78L-82
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Yes..ignatz is 100% correct with the OEM rear sway bar ONLY advice:

This:https://www.mamotorworks.com/Corvett...le-34-602628-1


Not this one:https://www.mamotorworks.com/Corvett...r-kit-602590-1

Note the ends of the sway bar are DIfferent....You want the vertical rear sway bar holes, NOT the horizontal holes!

Last edited by jb78L-82; 03-29-2020 at 03:10 PM.
Old 03-29-2020, 08:55 PM
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dwalsh7093
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Is there that much performance difference between the styles?

Old 03-29-2020, 09:49 PM
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Originally Posted by dwalsh7093
Is there that much performance difference between the styles?
Not really, until the non-OEM design suddenly binds and increases your spring rate dramatically. This can cause traction issues that will make you wish you bought a Mustang instead.

If you have one of the aftermarket bars already, my advice would be to look at this thread, which shows a clever way to use a heim joint with the aftermarket bar and the OEM connection. It may save you some grief down the road.

https://www.corvetteforum.com/forums...r-bracket.html


Photo credit to @cagotzmann

Last edited by Bikespace; 03-29-2020 at 09:51 PM.
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Old 03-30-2020, 09:42 AM
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Originally Posted by Bikespace
Not really, until the non-OEM design suddenly binds and increases your spring rate dramatically. This can cause traction issues that will make you wish you bought a Mustang instead.

If you have one of the aftermarket bars already, my advice would be to look at this thread, which shows a clever way to use a heim joint with the aftermarket bar and the OEM connection. It may save you some grief down the road.

https://www.corvetteforum.com/forums...r-bracket.html


Photo credit to @cagotzmann
Thanks for all the excellent information. The rear sway bar came in a kit that I purchased from Vette brake products years ago and it is the horizontal after market design and I guess they are out of business now.
I think my way forward is to purchase and install a an O.E. system.I received a link from a member, Mid America has the bar for $209(looks to be only one size, 3/4") and the end links are $50/each.
Other suppliers only seem to have the aftermarket style.






Old 03-30-2020, 10:31 AM
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You need to know how big the front bar is to determine the correct rear sway bar size!

A general recommendation IMO is that if your front bar is LESS than 1 inch (7/8, 15/16, 3/4) than I would go with the 7/16 stock rear sway bar size.

If the front bar is 1 inch, 9/16 inch rear sway bar.

front bar is 1 1/8 inch, 3/4 inch or 9/16 inch rear sway bar. I have the MA GM style 3/4 inch rear swaybar with my stock gymkhana front bar of 1 1/8 inch with poly mounting and endlink bushings.....
Old 03-30-2020, 01:17 PM
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My 75 FE7 Gymkhana Suspension with front and rear bars came as:
1-1/8" diameter front stabilizer bar and a 7/16" diameter rear stabilizer bar, only FE7 had a rear bar.

Always thought the rear bar was a little small, but GM put it that way.
Old 03-30-2020, 01:27 PM
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Originally Posted by KenSny
My 75 FE7 Gymkhana Suspension with front and rear bars came as:
1-1/8" diameter front stabilizer bar and a 7/16" diameter rear stabilizer bar, only FE7 had a rear bar.

Always thought the rear bar was a little small, but GM put it that way.

Yes^^^^ My 78 L-82 4 speed with sport suspension came with the same bars, front and rear^^^^.

Remember ALL GM cars were mandated to understeer at the limit, thus the very small 7/16 rear sway bar. I changed to the 3/4 inch rear bar 15 years ago to dial out the understeer...my car has very neutral handling at the limit of adhesion....

Last edited by jb78L-82; 03-30-2020 at 01:28 PM.
Old 03-30-2020, 02:01 PM
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dwalsh7093
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Jeff you seem like you have a good handle on the suspension set—up. Thanks for sharing your experiences, and I appreciate your suggestions:

My front bar is 1-1/8” and the springs are 460lbs and KYB gas shocks all around.

So my thoughts are to go with an O.E. Style rear 3/4” rear bar. The rear spring I cleaned up and repainted best I can tell it is a 2 1/4 wide, 7 leafs / pad. Not really sure if it is a true HD F41 spring?






Old 03-30-2020, 03:07 PM
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I have 550 front springs with my 360 composite in the rear with the front 1 1/8 OEM bar and the 3/4 rear GM style bar. with 550 front springs. I think with your setup up I would go 9/16 inch rear bar but very difficult to give advice not knowing the car's current drive characteristics and all the specs of the current components. The OEM steel gymkhana spring was 7 leaf and the base spring was a 9 leaf.....

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