1974 suspension
 

Is the 1974 Z28 suspension different than the the standard coupe? If so what is different?

Most Z28 models have HD suspension, or what is known as the F41 package. This includes a little heavier front and rear spring, plus front and rear swaybars, plus the front swaybar is a little heavier than the std. coupe, which doesn't have a stock rear swaybar.

Can you add a rear sway bar to the coupe?

Yes, you can add a rear swaybar. It's not a bolt in on the frame end, as Chevy didn't see fit to install the threaded fittings in the frame if it didn't have a factory swaybar. I've done a couple for friends using factory swaybars and mounts. It's easiest if you buy a nutsert tool and install the two threaded nutserts on each side for the frame mounting points. Harbor Freight sells a nutsert tool for about $20. It comes with an assortment of nutserts, but I'd buy the 4 3/8" nutserts you need form a good hardware store, as not sure I'd trust the Chinese nutserts for this application.
The axle mounting is just a bolt on, and easy. Once the swaybar is bolted up, you can mark the frame holes for brackets. Then drill the 4 holes, install the nutserts and bolt the brackets on. Pretty simple job, and a real improvement to handling.

Thanks . Sounds easy enough. It should help the car with handling. what are your thoughts?