Troque arm in 69 chevelle. Can I use the exsiting lower controll arm mounts?

[shep]

I am getting ready to put a torque arm in my Chevelle, how will using the existing lower control arms effect handling?
Using the universal Speedway motors kit found here https://www.speedwaymotors.com/Unive...it,456220.html. Existing lowers are 22 inches but are angled out toward the tire, radius rods included in the kit are 23 inches and call to be installed parallel to the torque arm.

Forgot to say that I have heim's in the lowers, planning to switch to r-joint or something similar.

Thanks

[Vimes]

What is your end goal?

Personally I'd stick with the triangulated 4 link (Tri-4) that the car has, and just replace the heavy stamped steel parts with stronger, lighter tubular bars. The Tri-4 is an excellent all-rounder design for a live axle, and I certainly wouldn't replace it for a torque arm. The torque arm will require a Watts link or Panhard bar, the Tri-4 handles that natually so that extra parts/weight/complexity is not needed.

That being said, structurally the outer link mounts would be strong enough as they are already designed for controlling the rear axle. The torque arm will control the force that was controlled by the upper arms, so there won't be any real additional strain on the outer mounts. It's been a while since I've been under an A body but I don't recall the lower arms having that much of a spread angle to them. As long as the lower bars on the torque arm are parallel to the ground with weight on the tires, I wouldn't think a spread angle front to back will matter on how well it operates. The Watts/Panhard will be there to keep the axle in line, and there won't be that much suspension movement up and down for the slight angle to matter.

[shep]

Goals are fun driver, and autocross car, I realize my goals are completely achievable with the stock 4 link. Thank you for answering the question.

[raustinss]

I'd stick with the above advice aka the kiss method . There's tons of guys still running a stock style rear suspension setup and doing it quite well . I've thought about everything from stock setup /stock with watts link ( hard to do plus mod the gas tank)/ c4 independent/ 5th gen camaro independent... I just keep going back to stock set up done right its easier ,cheaper and does everything for the everyday driving very well

[dhutton]

Not to pile on but give some thought to exhaust routing before starting. The tunnel on these a bodies is very narrow and shallow. Not to say it can’t be done…

[shep]

A little more info about where I am in the process.
The body is off the frame, doing ABC mini tubs, so if I do the torque arm we can cut out the cross member the stock upper mounts attach to and re do it with smaller tubing giving more room to run the exhaust up and over everything.
The torque arm attaches to the bottom of the rear axel under the drive shaft so it doesn't take up any room where the exhaust would be on either side of the driveshaft, just hangs 2-3 inches below the rear housing.
The concern is how the lower arms being at an angle vs parallel to the torque arm will affect handling. I'm not 100% sold on it at the moment i don't want to do something that will cause the car to be unsafe or or a pain to drive.

Thanks

[Vimes]

OK, that's different. Since you're that deep into making mods, forget everything I said before as I thought you were driving the car right now and wanted to explore making a change.

I don't think you will have an issue if the width between the front of the bars is narrower than the width of the rear. Ideally the front and rear width measurements will be the same, but they don't have to be. If you look at a truck arm suspension, it has the lower arms stretch from the rear diff about 4ft or so apart, and mount to a crossmember at the trans output shaft about a foot apart. A torque arm suspension is pretty much a truck arm suspension with much shorter lower arms. Truck arm suspensions are used by NASCAR for their 200+MPH cars, so you should be good on that. Of course, since you're making major frame mods anyway you could also just move the front lower mounts so they are in line withld each other.

Something else to consider would be a 3-link, which attaches only one top bar to the passenger side of the rear diff. It would still need lateral control, but would have no issue at all using the existing lowers. It would not reuse the existing uppers, and would require a new mount/crossmember to be fashioned.

[chevelletiger]

I was going to integrate a speedtech 2nd Gen camaro torque arm i bought from Keith (custom works performance)
And made a plate that attached to the diff cover on my 12 bolt,but the issue was i didnt want to fork out the money for the billet part that clamped onto the 12 bolt snout,and heard the diff cover on the 12 bolt would leak with the ta movement.

Plus I made a crossmember out of 1/4 steel plate and when I tacked it in i could push up on it from underneath and it would still flex,ideally you would want to make the mount sandwich between the top of the frame and the middle body mount,aluminum would be needed for that body mount,and I felt that would work better that one welded to 1/8 boxing
frame plates.

Also if you plan to go that route you would need a narrow depth gas tank because there isn't room for a PH rod bar or watts link back of the Aboy platform.
I ended up modifying the upper trailing arm mounts per Tony at abc performance which allows the roll center to be changed for road race,autox,or drag racing.
Shoot I still have the speedtech TA for when and if I get a camaro!
Here's 2 pics that tony sent me,mine is not as nice because I did it with the body on which was hard to cut and weld the 3/16 bent plates i made.
Its all welded up with full penetration on both sides.
I bought a c6 Z06 a few yrs ago and dont think I could build the chevelle to handle anywhere close to the Z06 for the price i paid for the Z compared to the chevelle.