I am wanting to swap 83' gears into my 81' and was wondering how much of and rpm drop I can expect at cruising speeds. Right now at 65mph I am running about 4300k.
Running the 83 gears with the 17" rear wheel you'll get almost a 500 rpm reduction.
I did this on mine and found the ratios are a bit "off" meaning the torque isn't quite there at the right times with the 17" wheel. I put the 16" wheel back on and it's much better..