Note: I'm not placing Steve's email to just sell he products. The email is to help you address your suspension issues. Steve is knowledgeable and offers ways to address these issues from his experience. Modded Mustang deleted my post above thinking I was selling. I wasn't, I wanted to share the knowledge. Steve may sell quality parts. But he will also steer you in the right direction if he doesn't carry what you need or supply you with simple home remedies for your stang. In other word " I trust him".
Below is Steve's reponse when I told him about Modded Mustang and helpful words on those noisy suspension.
Thanks Henry
Begin Here:
Yeah, sometimes forums get pretty cranky if a vendor appears in any way to be trying to sell his wares thru the regular forums. I suppose unchecked, you would have a hundred vendors answering every guys questions with a generic answer that says his product is the cure.
On the same token, it's almost annoying when you know you've got exactly what the guy wants, and can't tell him that due to forum rules. That's life I guess.
I was reading the post on mustangboards.com, and I've got a couple thoughts about the whole subject that I wanted to share. First off, really worn-out factory bushings can clunk, because basically there's nothing left of the bushing and some hardware bangs around in there. Most guys buy some aftermarket control arms at this point, since they have to do something anyway. But when they put in the greasable poly bushings, they find that they can squeek if you don't keep them lubed up often. Which makes a darn mess. Anyway, over a couple years, the grease breaks down the poly bushing, and they're back to square one. At least at that point, I guess they can just buy poly bushings, since most arms use generic Energy Suspension bushings.
As for clunks, short of the bushings being shot, they should probably look elsewhere for the real culprit. First I would closely inspect ALL of the bushings. Next, I would look for a cracked sway bar (sometimes Cobra rear sway bars crack near the ends). Then, I would ask myself if the car is lowered, and if so, is the factory pinion snubber hitting because the car is lowered. You could reduce the height of the pinion snubber, or just eliminate it entirely. I personally don't think it does a whole lot on most Mustangs anyway, unless you seriously bottom out the car on the suspension. Using many decent aftermarket suspension parts, this becomes less likely to occur in the first place.
I doubt shocks are ever a problem, unless the shock bushings go bad. This normally isn't a huge problem, but it could certainly be checked just in case. Internal shock problems are unlikely, in my opinion. Next, I would ask myself just how badly this car was beaten by the owner, and specifically drag launched with good traction, such as slicks. The factory torque boxes (the part of the floorpan where the control arms bolt to the body) are not designed for hard jolts, such as launching on slicks. As we stiffen up the control arms and bushings, and as we add slicks or sticky tires, we increase the jolt that is transmitted thru the control arms and into the floorpan (torque boxes). The upper boxes have basically just sheet metal with a bolt thru it that connects the control arms. The lower boxes have their front control arm mounting bolt go thru the frame, but only on one side of the bolt. The other side is supported just by sheet metal. If you could imagine a piece of 16 ga sheet metal, with a 3/8 hole drilled in it, and a bolt put thru that hole, that's pretty much all there is transferring the power and traction of the rear end into the body. That's weak. Given great traction, like slicks at the track, it is very easy to tear up these boxes real bad, or even just slightly wollow out the bolt hole. Now THAT could makes some serious clunking noises. The best fix, and I recommend it for any Mustang that's modified hardly at all, is to weld up the seams on the upper and lower torque boxes (pull the rear carpet and seats to do this!), and then weld in both an upper and lower torque box reinforcement kit, such as this one from UMI Performance...
http://umiperformance.com/1001?category_id=3
Notice the pictures in the bottom right corner of the page? They're of the install in my green 97 GT. :-)
As for clunking, I would also look real hard at the exhaust system, and the U-joints.
Best regards,
Pontisteve