A rubber hose is your friend when changing plugs on a 4th gen f-body. Stick it on the end of the plugs and the hose will act like a universal joint and helps get the plugs to thread in.
I've been able to change all 8 plugs on my stock '83 z28 in about 45 minutes. That's using 2 different extensions and a universal joint socket and contorting my arms under/around brake lines, smog tubes and the steering shaft.
