The KK needles fit the red backplate from the Cox Black Stuka engine. The needles even look the same. I also have an unknown white Cox backplate with the same threads. I screwed one in a couple of days ago just to see. I was thinking about making a remote NV.
Hank Nystrom at Texastimers sells a 128tpi NV that supposedly presses into a Norvel. I've been meaning to compare the measurements but haven't gotten around to it. He's still closed until Jan 11 or so. I think it would be easiest to just chuck the venturi in the box and put the new NV right through the holes in the engine. Bore them to fit and JB Weld it in place. They are splined too, so it should fit nice and tight. It might go into the hole where the old NV is. That way you'd still have the screen. A screen is good for me.