Fuel Line Thread Size Help

On the chrome fuel line that runs up to the engine, right behind the alternator, there is a threaded tap. When the nirtrous was hooked up, there was some type of line here connecting the nitrous, my fuel pressure gauge, and the fuel line all together. I have taken out the Nitrous and am now trying to mate two female ends, the gauge and the fuel line together. Cant figure out what size thread the fuel line tap is, nor the steel braided line to my gauge. Anyone have a clue? Is this a factory line?

I can't post a picture but I think I have figured out the issue anyways thanks to a local race shop. thanks for checking with me. we can let the post die.