I like Denso plugs, IT16 is the same heat range as the NGK TR55-ix iridium plug,
IT20 is colder and IT22 is colder still. the gap on the Denso plugs are .044 , i open my gap
out to .052 . the center electrode on the Denso iridium plugs are 0.4mm compared to 0.6mm on the NGK iridium plugs.
A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.
rods789 at sbcglobal.net
PB 14.474 @ 96.248 PB 60' 2.168
180 therm k&n filter
3.33 pulley 3" cat back exhaust
custom solid front motor mount
custom 6" (BIG) intake
___WCBF '06, '07 survivor___