You could get brand new carbs.

After dickin with my father's Tunnel Ram for a while, he agreed to spend some money to try something different. He had 650's on his, with a mile 400-450hp Chevy in it.

Well we tried double pumper 450's, they are only $230 each! They worked much better. Better throttle response, and much better fuel useage. Wide open on that boat was just over 5000RPM anyway, it didn't need much carb.

Summit's part number for the 450's is HLY-0-9776