im running agpr 902p motor craft plugs i realise i should have gone for a better plug heinsite an all that but going to run these first saying that i now someone runs them with a saff 380bhp with no issues im on stg 1 2wd saff. i no with a std coil the gaps have to be closed up but now ive fitted the grp a coil what is the best gap ive allready noticed after starting it tonight it idles allot smoother thanks ray

 

I doubt it's much larger, it's more due to the ignition system where the misfiring lies, although the plugs can count to an extent.

The coil you have will provide a stronger spark, so you may be able to open them slightly more.

Martin

 

when i had that set up gap was 0.6..

 

I have used these for many years, and have 1mm gap with grpa coil and 1.5 bar boost

https://www.msdperformance.com/produ...ver/parts/6201

 

Same here

 

ill go with 0.6 then thanks chaps