The No. 10 - 32 that Jon mentioned for the air horn
is also the same screw used to attach the main well support.
Therefore, the main well support screw will attach your air horn
if you have No. 10 - 32 air horn screws.
Chevrolet lists the;
No. 10 - 32 length at 9/16.
No. 12 - 28 length at 15/16.
Both screws should have a washer.
