Jeez, finally someone older than me that runs model tunnel boats!!! Great to have you aboard, Jack.
About the O.S., in NAMBA Stock, you can run a remote needle/mixture control but the stock needle-valve assembly must also be in place. This cost Rudy Formanek a second or third place finish at the last NAMBA Nats. Rudy had been running his boat in 7.5 Mod and simply forgot to install the K&B remote needle-valve when he entered the boat in 7.5 Stock. There was no performance gain by eliminating the the K&B needle, but that's the way the rule reads.
You are not allowed to make any modifications to the carb.
Jerry D.