I am curious how you did this with mcmaster # 48935... Looking at the picture and reading the description, which is (with a few snips to keep this messagew short):
They also convert to pressure-relief valves (not pop-safety) for low-pressure applications. Pressure adjusts from 0-20 psi with the knurled adjustment screw. Valves have a Type 302 stainless steel spring.
Connections: NPT male bottom inlet and vented top outlet.
It seems to me that this walve would have to essentially take place of your wastegate completely. Why I say this is because it says nothing of the outlet being threaded... Unless of course Im reading the sentence the wrong way
Looks like a great alternative to the dawes one, since its probably more or less the same item, I just put it together myself...
Thanks,
JMH