I have a set of front springs from a 89 RS 305 car and a set of 92 Z28 springs. The RS spring shave around 175k miles on them, the Z28's have only 32k miles.

I thought about swapping them out, but the RS ones are about 1-1 1/2" taller. The Z28 springs have one less coil. Both are stock and have never been cut.

I have taken quite a few pounds off the front of the car and dont want it to sit taller than it was. The RS springs were the ones on the car.

Is there that much difference between the springs? Will I be too low with the Z28 springs?

The car will be for drag racing and weekend warrior. No daily driving or autoX.


thanks for any advice.

 

Ok guys

I found some more info about the difference between the springs.

RS Spring #5604

Inside Dia. 4.090
Bar Dia. 0.671
Install height 11.00"
Load in Lbs 1760
Spring rate 347
Free Height 16.00"

Z28 Spring #5662

Inside Dia. 4.085
Bar Dia. 0.750
Install height 10.75"
Load in Lbs. 1690
Spring rate 748
Free height 13.01"


Do you think the Z28 spring will be ok? I removed the smog/AC, ft swaybar, and cruise. I went to aluminum heads and Lt headers. I am also switching from a 700r4 to a th350. I may be going to a fiberglass hood also.

I dont want the front to be too high. I know it is trial and error, but which should I start with?

 

Rhe Z28 springs will be less affected by the weight reduction than the RS springs because they have a higher spring rate. To achieve 1" gain in ride hieght you would have to remove 1500 lbs from the front of the car (748 lb/in springs x 2). You would only have to remove 700 lbs (348 x 2) to raise the car 1 inch with the RS springs.

It sounds like you are building a drag racer, which means that you would want the softer springs in the front to help with weight transfer even though they will be more effected by the weight reduction. If I was you I would cut the RS springs. If you want to keep the same ride height maybe take out half a coil or so. You will want to use a torch, do not quench, and bend the end to make it look flat like it was originally.

If the miles on the springs bother you a new set is only $51 just about anywhere.

 

The car will be used on the street some. I think the rs springs will be the safest bet. They worked great at the track last time. The car transfered weight just fine.

Oh well, it was an idea.

Anyone want to buy some low miles Z28 springs?

 

Sorry I'm not interested, I have the exact same springs in my car now and they are too stiff!

I think you'll be much better off with the RS springs.

 

If the RS spring from the V8 car dont work out to your liking you might want to try a set from a V6 car...........jt

 

I will keep that in mind. Would the v6 springs be better for weight transfer?