If you are going to remove the plug and gut it I highly suggest you use a 6pt box end wrench to remove it. The bolt head is thin and it's soft aluminum. Mine was stuck on there pretty good and I destroyed the bolt getting it out. The threads for the brake lines are even more sensitive to cross threading. At the end I said eff it and got the MM delete kit. Nobody makes these prop valves and they are pricey if you mess it up.
Good luck bro!
P.S. Any updates on the car?