Erik, What pressure fitting are you talking about? If you are reffering to a system that works off of crankcase pressure, there is a crankcase pressure nipple on all 4-strokes. If you're using a 2-stroke, you'll have to examine your engine (As in - take it apart, or at least remove the back plate) to find the best place to tap it.

Mark, Yes - if you look at the pics above, you'll see that one end of the pipe has a larger thread (Note: this engine is a YS 110 ) the larger side goes to the head, so I tapped it as close as possible to that side in order to: A) get it as close to the hottest part of the exhaust, and B) give it the longest time possible in the heat.