Parts numbers are on the gnttype.org site as I recall. They are certainly in the archives. Buy them from a discount offering GM dealer such as Vandemere Olds...also listed on the site. Ask for Dal.
Easy to replace unless you are doing the GNX bushing, then you have to pull the rear bumper back and jack the car up higher to slip that bushing in. (pull the bumper back to keep from smashing the fillers)
have to watch under the hood to make sure nothing gets crunched behind the coil pack as you elevate the rear of the body.
Only real hard thing is trying to get rusted bolts out of a northern car without breaking off the welds inside the body....
If you want an improvement you can feel with about 20 minutes of work, order six 457915 Lowers (the stiffest one) and replace the washers that are located back by the gas tank, just in front of the rear wheels and at the middle of the doors.
Dal sells them for about $7 each (maybe less) so thats about $42 shipped.
I bought a GNX upper and lower, too, but that takes more time to install (as Steve said)
The way I do it is to remove both bumpers.
Take the bolts out from one side only and jack up the body, bracing it with 2X4's.
Assuming you want to do this to improve stiffness and handling, replace all bushings, upper and lower. Order ALL the body bushings for a Monte Carlo '87 or so, and you will also get the "GNX" bushings for the crossmember at the fuel tank.
The price from Courtesy Parts last week was just over $200 for all. The expert there is Jeff Green at 888-604-3020
3334 W. Marconi Ave
Phoenix, AZ 85053
602-866-9908 [email protected]