Question about "twin plug"

[126coupe]

I am performing my piston to valve clearence check and I ran into a problem.

I thought it would be a good idea to put in the spark plugs to see if everything was OK, well the relationship to the head bolt is so close you cannot get the spark plug socket on the spark plug. Did the machine shop screw up on the maching of the spark hole? I cant imagine putting the spark plug in first and then torquing the head bolt......no way!
Yes I am using the smaller profile spark plugs.

Suggestions please!

[126coupe]

Oh yeah the photo

[TimT]

Change your head nuts to ARP or similar jet-nuts, or use a plug such as a NGK R5671-8

[126coupe]

I am embarrassed, I never dealt w a twin plug.

I was supposed to use a nut on the head stud not the factory head nut

[TimT]

You can use the barrel nuts if you use a plug like the NGK I mentioned. Or you can change the barrel nuts to jet-nuts.

That p[articular NGK is full sized thread, but small dia wrench plug

[Henry Schmidt]

With Supertec head studs, spark plug clearence is never an issue.
We use NGK 6Ekub. We have had exceptional service from these twin electrode plugs.

[126coupe]

Thanks Guys, but since I already have (24) BR8EIX on the shelf I used 15 mm /ATF nuts, which I had available.
Cams were just delivered. now I can finish assembling the engine. I should have all the ignition parts by tomorrow.

[ChrisBennet]

I just use a reduce wrench size nut - 10mm nut that takes a 15mm wrench instead of the usual 17mm wrench. Porsche uses them on the engine carrier bracket in some places.
-Chris