Use the original carb. The one jetted for the 261 will run a little lean because it's set up for more airflow than the 235 can produce. Contrary to logic, a carb for a larger-displacement engine delivers less gas, not more, when it's installed on a smaller engine.
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!