A float tends to get higher with use from the constant upward thrust of the float against the needle valve. Even if it was set right when the carb was assembled, its position can change over an extended period of time. This is more common with Carter carbs, as Rochesters usually don't run long enough between rebuilds for that to happen!
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!