Is he simply unbolting one carrier assembly and installing one with a different ratio? I could understand that being a 20-30 minute job, but swapping the ring and pinion into a carrier would take more like 2-3 hours to do it right, and a lot more equipment than the average swap meet vendor would have at his disposal.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!