Modifying retro valve

[damajor]

Just want to clarify modifying the retro valve to accept the ULT. The valve needs to have the taper drilled out so that it's flush with the bottom of the existing small oring...this oring is removed after and the ULT sits in the valve flat? I want to take mine to a local machine shop to have this done and just want to clarify!

[211]

thats what you need to do
make sure you are working with a competent machinist, if its wrong its scrap