I have a straight BBA ASA input thread.
Making a 2nd thread for a Phantom Style Side Air Valve.
Choices would be....
Single Port Right
Single Port Left
Dual Side Ports (Left and Right)
Rear + Side (remote and a gauge perhaps?)
More holes=more money (keep that in mind)
If I made them, they would be
-Flush with the back of the frame
-Steel Thread insert for Grip screw
-1/8npt pipe threads in the ports