nos on a 318

Tune up the car to run the best it can without juice, then add juice.

You have a bunch of stuff to work on before messing with the bottle.

Gearing on juice is different than without. The 3.91's you have might be good with juice, even with the taller tire.

If you do put the 125 on, pull 4* of total out of the ignition and make sure your fuel supply and plate jetting are appropriate and correct.