The 3.73 is probably the best possible gear- - - -don't mess with success. A 307 has the same stroke as a 327- - - -3 1/4 inches, and it can live comfortably at 6000 RPM or more if necessary. My race engines ran 6K-7K RPM all the time. Depending on tire size, you're probably going to be under 3K at highway speeds, which is just loafing along for that engine. If you want a Cowboy Cadillac that's only going to carry a Yeti cooler to tailgate parties on weekends, go for the 3.08. If you want to do real truck things, stick with the lower gear.

Swapping the direct drive 3 speed for one with a Borg-Warner overdrive would get you the best of both worlds.
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!