OK- - - -more information is always good! With a 265, you should be able to handle a higher ratio than the usual 235/automatic setup. Do a little research on the axle ratio a mid-1950's Pontiac or Oldsmobile ran, and gear your truck accordingly, especially if you're building a highway cruiser instead of a load-carrier.
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!