Late 31 zenith 2 carb rethread

[sphooch]

Has anyone ever repaired the threads in the side bowl gas inlet?? its 1/2--20 N.F. . I ran a tap through but it leaks like a sive from there . the threads are in pretty bad shape as you can see from the picture. I'm thinking maybe using a heli coil . but don't know if it will work. Maybe braze the thread and then re-tap? this is gonna be a tough one,any help is always appreciated. thanks THE HOOCH