Need help with suspension components, when the rear is not stock.

[Hi-Fi]

Hey all. Just picked up a 87 Monte Carlo LS that has had some work done, but is in dire need of suspension and brake work. Since I'm going to be replacing most of the front suspension and brakes, I'd like to do the lowering at the same time, it looks like about stock height but I'm not sure.

The rear end was replaced with a Ford 9". Since the springs sit on top of this, I have no idea if they're the stock springs, if it would sit higher or lower, etc. I did measure the spring though. With the weight on the car it is 10" tall, with no weight (spring loose in cups) it's about 12 5/8". Can anyone confirm if the stock rear spring is 12 5/8" tall? Not sure where else to start. Car needs to come down about 2" in the rear, maybe 1.5 in the front. No budget for a coil over setup

 

[565bbchevy]

I don't know what stock height springs would be in the rear but I have a 9" and used UMI's 2 " drop springs in the rear to lower it.

 

[Hi-Fi]

Looks like good wheel gap. What size rear tire is that?

 

[565bbchevy]

Looks like good wheel gap. What size rear tire is that?

The rears are 295/55 MT drag radials on a 15 x 9.5 rim with a frame notch.

 

[pontiacgp]

I think your rear spring are a higher spring rate than what's on a G body. The free height of the G body spring is from 14 3/4" to almost 15 1/2". The height of the spring with the weight of the vehicle is 10 1/4"

 

[Hi-Fi]

I think your rear spring are a higher spring rate than what's on a G body. The free height of the G body spring is from 14 3/4" to almost 15 1/2". The height of the spring with the weight of the vehicle is 10 1/4"

[Good to know. It feels pretty firm in the rear. Sounds like the overall height of the compressed spring is similar, so a 2" drop spring should drop it around 2".

The rears are 295/55 MT drag radials on a 15 x 9.5 rim with a frame notch.

Thanks!

 

[pontiacgp]

UMI would gladly help you out and they have the Green Machine that they test all their parts on

 

[ssn696]

This may be responding to an old question, but I believe Ford 9" axles and conversion kits put the spring perch and control arm pockets in the same relative locations on the axle as the 7.5" factory axle.

 

[UMI Sales]

I think your rear spring are a higher spring rate than what's on a G body. The free height of the G body spring is from 14 3/4" to almost 15 1/2". The height of the spring with the weight of the vehicle is 10 1/4"

Agree. Our 1" lowering springs usually sit at around 10-1/4" compressed and 2" lowering springs around 9-1/4" compressed.

This is from top frame bucket to face of pad on stock 7.5" axle.

If you mock the car up without springs and measure, you can get an idea of where it'll sit at around those compressed heights.

Of course your results may vary a bit due to car weight, etc.

ramey