I just finished roughing in my $35 kick down switch set-up. You can use this on all three years. I made it in less than an hour. The best part, I think, is that you don't have to alter anything. Not even any holes drilled in the car body for mounting. The bracket is made of a piece of angle iron. The clamp is obviously an exhaust clamp(2"). The switch is a real GM Turbo 400 kick down switch. They are available for $20 at
http://www.oldsparts.com/