Reply To: .25 Marauder low power tune
The gauge block can have an offset hole milled in it so that the gauge adapter threaded hole is not effected. You can also simply remove as much material as possible without ruining the threaded adapter hole.
For the valve, there are all different things that can be done. I turned some off the stem side outer face. Bored out the inner ID for volume as well as opened up the end cap. I opened up the valve throat as well as the exhaust port. The valve spring was also changed.