Plugs and how to read them

This may be a (no brainer ) some of you guys,but you only find out by asking -- I,ve been running NGK BP8ES plugs in a blown inj alky motor in a rear eng dragster -- they have a golden color coating on them ,and we alter our jetting (hat inj only) according to how far down the earth electrode the heat goes -- this is indicated by the platin being burnt off -- when we get it down to the first threads then we now that its damn close -- this may seem a crude method to some of you guys but its got me down to 7.3 @180
Now -- i,m finding it hard to obtain these plugs over here , and last season we bought 50 plugs for a meeting (we throw them out after one run ) and 14 were duff . So if i change to say Champion -- can i still use the same method of reading them or do i have to change technique completly -- thanks guys -- and if you feel i deserve some micky taking---- i wont be offended -- John Every Penny Racing

 

hi,john.
are you running a super mag 3 or 4 .
we ran b9es with no trouble with super mag 3,s.
we have a few boxes left as we switched to a cooler plug when we went to the 44.
email me if you want .
you have my address.
cliff