Here we go again, WHAT SPARK PLUGS

I've never had a problem with NGK. They are a good plug.

ANY Suggestions to those who've experienced this? I MAY BE IGNORANT BUT STILL LEARNING.

i put ngk gr5's in today.
when i snap the throttle from idle (around 900rpm), the time between the second i snap the throttle and the rpm takes off is a good 1 second or more. the fuel is shooting in good from the nozzles as the eye can see.
what should i be checking ANY ORDER TO START?

IT IS A 340 with 4 speed 484 PURPLE CAM
holley fuel pump regulator set at 7 psi
i'm running the msd non vac mechanical dist. msd7al-3 with coil.
holley 650 cfm now , but not sure if that is my problem
i set initial timing to 18-20 degrees and 750-900 rpm. ran it 8-10 minutes.
hit WOT then shut it down. the new plugs are white all aroung except where its rather dark brown near the stem/electrode.
almost as if it's too rich. there are some eye burning fumes from the tailpipes. Stock jets in the 650 cfm double pumper.