Use an X-acto knife or a paper punch to modify the new gasket to expose both holes- - - -problem solved. If you're tinkering with the cable bracket, just make whatever modifications you need to make sure all the cables line up properly- - - -it's most likely possible to fabricate an add-on piece to avoid making permanent modifications to anything in case you decide to swap back. Not likely, as most people who make the Rochester to Carter swap can't believe how much better the engine runs with a Carter carb.
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!