Adapting a column shift to a 5 speed overdrive transmission would be an engineering nightmare! There's an RPM calculator formula somewhere in the tech tips section that allows you to plug in such variables as tire height (the 27" figure quoted), rear axle ratio, transmission overdrive ratio, etc. and figure out your engine RPM at a particular road speed. As a ballpark guesstimate, running a stovebolt engine much below 1800-2000 RPM in top gear on the highway will cause massive losses in fuel economy because the engine is lugged down below its comfortable torque range and the power valve in the carburetor will open up. Simply lowering the highway RPM doesn't always translate to a fuel economy or performance advantage. Make things work on paper before you start swapping parts!
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!