I have a Silverado with a D1 at 10 psi. What spark plugs is everyone using and at what gap?

 

NGK BR7EF are a good option and somewhere around a .025-.030 gap.

 

If your gonna use a heat range 7 then tighten the gap to .021-.024

 

NGK BR7EF's here with Procharger and 9lbs. Gapped at .028. No spark blowout issues.

 

You could probably get away with a TR6 in this case. The reason why I bring that up, is because I don't think the NGK 7's are a resistor plug. While most don't have issues running a non-resistor, it can happen. I'd do the TR6 around 0.025" and not worry about it. I like moving to a 7 around 14 lbs of boost, but it's a topic that is easily debatable because they should both work fine.

 

The r in the part number stands for Resistor.

 

I use Delco AC 41-104 gapped to .040" at 15.5 psi

 

What plugs and gap would you recommend for a 5.3 at 8 psi with a 1900?

 

At 8 psi a BR6EF should be fine gapped at .030-.032

Just my opinion though.

 

I just went through this mess in June for my 2500HD 6.0L. I tried NGK plugs gapped at 0.035 but the spark blew out when the water was introduced at 2 psi. Went back to AC Delco standard copper plug for a 2002 6.0 gapped at a loose 0.030 and no more spark blow out.
The engine builder did not want to move away from a plug that has worked well for us for over 115,000 miles on a 216,000 mile engine.
I am not the mechanic I just give him money and he lets me drive the truck for a while, then rinse and repeat.