I'm new to this site so here are my questions:

1. I want to ADD rear sway bars. I've seen F40 and F41 sold on E-bay.
What are the differences and what are the stock ones.
What cars in salvage yard should I search for rear sway bars.

2. I can't find any numbers on the rear axle to identify the rear end type.
The only identifier is a metal tag saying "USE LIMITED SLIP DIFF LUBE ONLY". I READ THAT DOESN'T GUARANTEE ANYTHING.

Thanks for your help :?

Rear sway bar is 7/8. The bar is the same for all packages. For the axle code, the numbers are on the inside(toward the front of car) passenger tube. You will probadly need a wire brush to remove the grime so you can see them. Oh yea, Welcome to a great site. :)

F40 Heavy Duty Front and Rear Suspension
F41 Special Performance - Front and Rear Suspension

The F41 suspension was standard on the Monte Carlo SS. The F40 was just a heavy duty suspension package. The F41 had larger diameter front and rear sway bars. Both packages also included the front jounce bars and different springs all around.

For info on finding the axle code go here. (http://www.geocities.com/malibunirvana/technical/rear_ends/axle_code.html)

What cars in salvage yard should I search for rear sway bars. Similar year Montes & Buicks

The only identifier is a metal tag saying "USE LIMITED SLIP DIFF LUBE ONLY". I READ THAT DOESN'T GUARANTEE ANYTHING. True, but it is more than likely a posi unit. Check the codes on your RPO sticker inside the glove box.

If you have a stock 87 with a V8 you have either a 2.41 or a 3.08 rear end. The TBI V6 came with either a 2.56 or a 2.73 rear. Those were the only four choices in 87.

There are 16, 19 and 22mm rear sway bars. All are better than none. Measure them, because F41 meant different things for different years/models.