The repair and workshop manual recomands Champion UN19V gapped to 1.27mm. The blue manual recomands Champion N60Y gapped to 0.4-0.5mm. This forum recomands NGK BP6ES (?gap?). Got a lot of misfire above 4000rpm when I gapped the BP6ES to 1.27mm. Which one is right? Raymond
0.6-0.7mm is best. The early manual had a crazy small gap, that was later corrected due to fouling. You'll also find a Dino runs sweetest on a fine tip plug, like an EVX or even EVIX (iridium), but a decent tune is important! It's also quite normal to have a higher heat range. BP8EVX, so long as your fuel quality is good.
Dinoguys - a gap of 1.27 MM (.050") is definitely on the high side, although the Dinoplex might marginally handle it. The absolute best setup I've found on a Dino with the 'plex bypassed is the NGK BP5ES or BP6ES, set to .035". As the gap is increased, a higher potential is needed to jump the gap and therefore more energy is discharged across it. Less chance of fouling. I use the BP5ES in my 330 along with Bosch Blue coils and, in an older car like mine with many miles, it is a prefect setup. Bob Z.
Apart from the electrical theories of spark voltage, the smaller gap encourages fuel and oil to bridge the gap potentially causing a short circuit.... especially during cold starting and excessive low speed use (traffic)
