this is debatable
i change gaps and plugs depending on the sintuation i am in and compression of the motor.
the higher the compression the harder it is to ignite the fuel so a stronger spark is needed or you will get miss fires, an easy way to get a stronger more reliable spark especialy with a weak ignition syst like ours is to close up the gap... a smaller gap makes a stronger and more reliable spark but it wil be slightly smaller
a larger gap will misfire under high comp but because of its longer spark it ignites more of the fuel faster and more compleatly under lower compression ratios
if your running stock compresion and do not have a x chamber to raise dynamic comp then go with a standard gap of .025 but going to 30 could net you better gas milage, you should gap it as large as you can without afecting the reliability of the spark and the ignition of the fuel
also iridium plugs do work wonders and seem to stay clean and are more forgiving in thease motors. they are a must under super high comp 12:1 and over