I have an '89 Formula and would like to replace the springs and shocks on the back of the car. I want to get the factory ride height and noticed the MOOG replacement springs available at summit racing. They are available in Variable Rate or standard rate, and I dont know which ones to go with. I'd like a more comfortable ride, but don't want the rear-end of the car to shoot down when I gun it (which is what it does now, prob cause the springs or shocks are shot). Which ones should I go with??? Is KYB or Monroe a better brand for shocks??? Thanks!
Ben

 

The variable rate springs may be slightly more comfortable, if they are a true progressive rate design or if the change in rate hasn't already occurred with the car at rest. But linear springs are somewhat more predictable when you're driving hard in the turns. Your choice.

You'll be much better off with either of the KYB's in an F-body (or almost anything unless it's an "old Cadillac" OE ride that you're after), with the Gas-A-Justs providing more control at a very small ride penalty.

As far as the Monroes are concerned, I'm assuming that you're talking about their "Sensa-Trac" shocks. About all I have to say about them is that they are something of an "anti-performance" shock and not very well suited to any F-body that ever gets driven very hard. Damping is intentionally reduced around the car's design ride height via a specific internal design feature. Sort of like having half-dead shocks right out of the box. Worse, if your ride height doesn't match OE specs.


Norm

 

Thanks for the reply Norm. One more question that I had was that I have A subwoofer, box and two amps in my rear and I don't like the traditional formula rear sag that about every stock formula I have seen has. I want the rear to be as high as the front if not a bit higher. Will the progressive rate help out with making the height even and compinsate for my sterio equipt.???

 

Progressive rate doesn't directly correlate to ride height. It does mean that they stiffen as they are compressed, which helps keep you off the bump stops.

For what you're after, you'll want a stock-ish height spring that's a little stiffer than OE. Believe it or not, it will ride a little better than stock rate under some circumstances.

One possible solution is Moog's Cargo Coil (CC635, according to my 11 year old Moog book). Unfortunately, I don't have any rate or height information for the CC series springs other than their being progressive. But out of curiosity, does that part number ring a bell?

If you end up being happy with the rate but not with a too-low ride height, it is possible to fab some spacers.


Norm