1966fastbach

I have a 1966 Fastback. Shelby drop,new roller spring perches and cut about 3 inches off the front springs. it actually drives really nice and front end alignment is spot on. tires wear normal. my problem is if i'm driving down the road over 20 or 30 miles per hour and i hit a decent bump or drop in the road especially if it is during a slight turn the whole front end starts bouncing and wobbling. once i hit the brakes a little it smooths right out again. everything looks tight underneath. at a loss !!!! anybody have any ideas ???

barnett468

hello;

more info would be helpful

of you hit a speed bump etc and the front end bounces like there is no shocks, yiu need new or better shocks.

if you try to push down on the front and it only moves an 1 inch, it is likely way too stiff which can contribute to the type of problem you are describing.

all the suspension must be in good shape., it your tie rods are worn it can do some of this, if your idler arm is worn it can do some if this etc.

if your inner lower suspension arm bushings are bad it will do some of this.
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67mustang302

Shocks also need to be matched to springs. So if you cut the coils you've increased spring rate, and with a shock that's too soft it may not be able to effectively dampen the motion.

barnett468

This is where its nice to have shocks that have individually adjustable compression and rebound. The stiffer the spring, the more rebound damping it takes to control bounce. Excessive rebound will cause "packing" over successive bumps. This is where suspension returns less far over each consecutive bump which reduces travel.

. . . . . . . . . . . . . 64 - 73 mustang

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http://www.strangeengineering.net/ma...re=default&p=2

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LynnBob Mustang

Cutting 3 inches off the springs seems excessive. I would go with the proper drop springs.
Lynn

Starfury

I'm assuming he means 3" around the coil, not a vertical 3". 3" around a coil is roughly 1/4-coil and makes much more sense.

Barnett, those are some pretty badass shocks...but holy crap, $1000 for a set? At that price, you better be racing with it. Maier Racing's Bilstein shocks are custom valved and cost half that, iirc, and I bet most people would be more than happy with them.

barnett468

hey...how are ya, where ya been?

yeah the strange shocks are kinda fancy and so is their price, but hey, they're shiny and the bilsteins aren't, lol.

Starfury

School. Last year of BA @ UC Davis. Taking quite a bit of time...

67mustang302

The custom valved Bilsteins from Maier are the "old" non adjustable shocks. The new (and better) JRI shocks are hellaciously expensive. It's basically equivalent to a Penske, which are also crazy expensive.

The Bilsteins are really good, and the JRI are absolute top of the line. You're not going to find better than a JRI/Penske etc without converting to an electromagnetic shock system.

$300 per shock with fixed valving, $750 for a single adjustable, and $1,250 for double adjustable. Per shock, for the front...rear shocks are cheaper. But a full set of double adjustable JRI is about $4,000. Penske's are in the same ballpark, astronomical.

1966fastbach

I should have been more clear. When i was going for the right height i would cut 1" of length at a time off the new stock spring and then reassemble and drive a while and then do it again. total of 3" was cut off the coils. yes it was a pain in the butt but i had a great spring compressor that helped alot.