Here's 1 of the metering diaphragm 8-32 barb. The other three are the velocity stack I just installed.

You just tap the vent hole on an angle for 8-32. Have somebody silver solder the thing in after you snug it up....not too tight. Or use red lock tite like I did. Then grind the inside almost flush so it doesn't restrict the metering diaphragm movement. Very easy to do.