YOUNG GUN: Putting Nitrous on 318!!!

If you have an A/F meter, tuning it is really easy. Get the A/F to where it likes to run N/A, either changing fuel jet or fuel pressure, MPH/plugs can be your guide here too... then start dialing timing back in 1 degree at a time, watching MPH and spark plugs.

I don't know what fuel pressure the NX kit wants as a baseline. Some want some fairly high settings. 6.5 is usually an acceptable/usable pressure. If your pump pressure is lower than the kit requires, you may want to put a slightly larger fuel jet in the kit than the jetting recommendation suggest. It's all a dance.

I'd take 6 degrees out to start. Better to take too much out and sneak up on the tune up than not enough.

My 2 cents, get more initial, 16-20, on it if it will start OK when warm. Limit total to your current 34*. That cam has a bit of overlap and the engine will probably run cleaner at idle with snappier response. It takes some work, but, the way it will run off idle and cruising will be much better.