Ngk buhw

[25two.stroke]

The 10 means the plug is pre gapped.

NGKs are all pre-gapped.
When brucato says that -10s are pre-gapped at 1mm it does not mean that the other plugs are not pre-gapped. They are just saying the -10 is gapped at 1mm which is more than they (and merc) recommend for the 2.5L. The -10 is a .039-.040 gap. The BR8HS/BR9HS is 0.032" I believe.
I run the BR9HS-10 or BR8HS-10 straight out of the box in my bridgeport, my 260 as well as numerous other modded and stock outboards I have. I rarely run surface gap plugs cause they are hard to read and I never run pistons so tight that they need the clearance.

If you are reading 0.035" on multiple -10 plugs (not a few that happened to get dropped) then your gauge is off. They are damn close to 0.040" out of the box unmolested.

[pkstv]

Actually I re gap my plugs to .035 and every box I buy are never the same .

[Chaz]

Rarely does the ground strap drop exactly straight down, parallel with the body. Nor does it make a perfect 90* bend with the inside radius perfectly square with the center electrode ... Wadda-ya want for mass produced @ two bucks a copy ..

Then they sell the same plug in two flavors .. 32 an foddy .. add in the home benders and the gap might be at one side of the center electrode or the other.

Feeler blades are for adjusting valves ..

The U shaped wire guy is for gapping plugs .. it either goes thru, or it don't ..