Hi Maddogg

Take a look at the picture of the back plate of the .61 RF it does have a boss for a nipple but it came blocked by a screw. If yours has a nipple installed, remove it and plug the hole. Pressure fitting placement on tuned systems (As per Macs Products)

The most consistent pressure is found where the pipe first reaches its apex in width. However, this may be inconvenient. Many modelers choose to place it in the header plate. The problem here is a possible pressure spike which can develop when the aircraft is in a power dive, out running the system tuning. The spike may flood the engine causing it to lean or die. (This occurs seldomly, though.)
Note: Never place the pressure fitting on the header tube or the muffler part of a tuned pipe.


Even though Macs recommends not to tap the header for pressure, I’ve never had a problem. Different installations sometimes require this.