control arm length

[rjselky]

This is going to be for a 65 elcamino. it is all stock suspension. My question is I've been thinking about changing the control arms for something after market and found that there are longer control arms upper and lower to change geometry. I want this to handle better on the street for now and may start taking it to a track eventually. It currently has a 454 bbc nothing special maybe 400hp and a th400. The car has the stock front sway bar and factory springs, a control arm for the back and good shocks all the way around wouldn't hurt it. Also what is a good control arm to replace the originals with? everyone claims to be the best.

[killer69]

Speedtech OBVIOUSLY!!!
seriously there are a bunch of good ones. our Road Assault package would be a great choice for what you describe.

http://www.speedtechperformance.com/...rod/prd130.htm

[rjselky]

thanks for the info, but can you or someone tell me the reason why some control arms are longer than others. I see your in St George, I used to live in Winchester Hills small world

[killer69]

There is no reason for different lengths?? Really the only difference should be the position of the ball joint fore/aft to affect caster. There really is a finite length required to make the geometry work correctly and be able to align the car after install.
where are you see different length control arms?
I know in the roundy round catalogue you can get different lengths but that is more to build specific stager and camber into the cars that can only turn left

[bret]

This is going to be for a 65 elcamino. it is all stock suspension. My question is I've been thinking about changing the control arms for something after market and found that there are longer control arms upper and lower to change geometry. I want this to handle better on the street for now and may start taking it to a track eventually. It currently has a 454 bbc nothing special maybe 400hp and a th400. The car has the stock front sway bar and factory springs, a control arm for the back and good shocks all the way around wouldn't hurt it. Also what is a good control arm to replace the originals with? everyone claims to be the best.

As Blake pointed out, the length of the control arm is only one of the dimensional changes that can be made to improve suspension geometry. the exact position of the balljoints in all three planes is critical and must be designed as a package to work correctly in the end. Camber gain, dynamic caster gain, scrub radius, and bumpsteer ALL are important if you are going to actually improve your front suspension. Unless you are a very experienced competition driver competing in a mid-high level style of racing, the nuances of a true racing or custom built suspension may not be noticed.
One of the "good" things about the A body GM suspensions is that practically anything you do to them is an improvement. The OEM GM camber curve is backwards...the tire goes into positive camber on compression. A taller spindle or taller upper balljoint helps that a bunch...the car feels much more stable through the turns. The bumpsteer is not terrible, but can be improved. Some aftermarket control arms will move the upper balljoints back and the lowers forward to allow more positive caster, which helps stability. Be aware that some inexpensive control arms replicate the oem geometry and do little/nothing to actually improve performance. Also be aware that many aftermarket control arms use a polyurethane bushing. Poly does help eliminate some unwanted bushing flex but typically at the expense of harshness induced by the "sticktion" of the poly. This sticktion is what causes the squeaking the you typically hear from a poly bushing. The best arms use Delrin, and in the case of our StrongArms and streetgrip packages, a self lubricating Delrin compound that eliminates both unwanted bushing flex AND unwanted sticktion. A simple concept, but it makes a much happier suspension.

I understand this all may overwhelming to someone who is just starting to learn about suspension. Keep asking questions. Sift through the answers to find the path that works for you.

[BMR Sales]

Blake & Bret are Correct! It's not just about length. The Geometry changes for the better is mostly on the Ball Joint Position

[j-c-c]

I agree with the above two replies, but back to OP question, in a properly designed suspension, a longer control arm is normally preferred over a shorter one, within limits, as already mentioned of cost/effort vs noticeable benefit, fwiw.

[UMI Tech]

I think you are referring to a-arms that have a shortened "cross shaft to ball joint distance". These Type A-arms are manufactured with adjustable rod ends and used in conjunction with taller ball joints to eliminate shims.

http://umiperformance.com/catalog/in...roducts_id=956

Craig

[TheJDMan]

The single most important thing you can do is to buy all your suspension parts from one manufacturer preferably as a complete kit. ridetech, SpeedTech, Hotchkis, UMI, etc. all offer quality suspension kits. I would recommend doing research on complete suspension packages and companies that you are interested in. Whatever you do, DO NOT BUY NO NAME EBAY SUSPENSION PARTS!!!!

[rjselky]

Thank you for the response. Yes most definitely buy all from same mfg. Ebay stuff always scares me it seems its never what it says, as far as some a-arms being longer the roundy round makes sense. It was just a question I had and I thought with a 50yr old car maybe it would benefit it but now that I understand I'm good. Thanks again for all the help