Don Terrill’s Speed-Talk

Thanks to some recommendations I bought ngk r5673-8 for my combination. I spoke with Jason Norwood of ngk and he recommended this plug also. My question is he said to leave the gap at what the plug comes out of the box. I’ve checked a few and this gap is a tight 20 at best. I was running 43 with my previous ac delco plugs. What’s everyone else running for gap??

If it is HEI, GM specified 0.060" gap. If you are using good quality leads [ which is anything but graphite ], you will be ok.

Ignition is digital msd 6Al-2 with built in 2 step. Blaster 2 coil and msd wires.

Not sure what your combo is, but I run .020" gap in my engine with NGK plugs.

The reason you run the NGK racing plugs how they are gapped is the porcelain gets so "short" that they can flash over as a surface discharge rather than across the gap, if the gap is too wide.

Some of those plugs need to be gapped as tight as .010".