Originally Posted by woodford rs
we always set it to .6 as it gives a stronger spark,but the standard gap is.8
A smaller plug gap has the opposite effect
Too narrow and the spark is too small. A larger gap gives a 'hotter' spark.
On tuned cossies (not running coil pack) you need to run a small gap to enable the plug to spark in the increased cylinder pressures AFAIK but this is far from ideal and should not be needed on a standard car surely?