Get a "Real" Carter carb for it, trust me.
I worked for Carter for 25 years, fact is I sold a New-in-the-box #9511 500 CFM carb about 4 years ago on Ebay.
But, ......... get yourself an 'Original' '60's Carter carburetor, they are correctly calibrated, not a universal calibration that comes with all of the aftermarket units that were sold by Carter and now Edelbrock.
I'll stop now, because I don't want to write a book on the subject, but just pick up the phone and call John at the Carb Shop in Eldon Missouri.
Call John and he will set you up: http://www.thecarburetorshop.com/