Rear spring swap question
Thread Starter
Intermediate
Joined: Feb 2008
Posts: 33
Likes: 0
From: ILLINOIS
Rear spring swap question
Hi, I am changing the rear spring on my "88" from a base spring to a Z51Optional (NYU) spring from an "89", can any one tell me if the shims are the same size, if not what size shims well I need...........Thanks
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
They both should use the same size shims. You'll have to bolt everything up and check the ride height. You may need to swap shims from top to bottom to get it dialed in or use longer bolts on the ends of the spring to give you greater adjustability.
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
GM designed the spring rates front and rear for best handling, best not to mix and match but usually cars are designed with a softer spring in the rear as most of the weight is in the front.
The easiest way to improve handling and control ride height, is to remove the composite springs and fit coil overs.
See the link below.
http://www.vansteel.com/index.cfm?fu...&SubGroup=1972
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Each spring base, FX3, or Z51/Z07 had specific spring shim package setups. The combinations found in the FSM. I know b/c when I changed my 93 FE1 base NYR spring to the NYU from a Z07 I looked up the shim combination in the FSM. You get one of those your golden.
