I have stock heads, and purchased NGK R-5671-A7 plugs as per Lloyd Elliott's recommendation. However, they are a gasket type plug....not tapered. Will they fit or no?

 

You should be using a tapered plug, AFAIK. Maybe he knows something different about it.

 

From his e-mail...

 

That's what I'm using. I wondered about that, but when I inspected the crush gasket closely, it appears that the gasket face is tapered. I figured that it would probably form into the tapered surface in the cylinder head. I put them in and torqued them like it said on the box (hand tight + 1/2-2/3 turn) and they seem to be working just fine.

 

I forget what Lloyd told me on the phone...whats the advantage to these again?

-Dustin-

 

Less detonation I believe?

 

-Dustin-

 

They're colder plugs...he said more timing / N2O / boost before detonating.

 

Putting a gasket style plug in a tappered style hole may effect the reach of the plug. I would check that first.

 

The threaded part of the R-5671-A7 plug is identical length to a TR55.

 

Correct....but when screwing a gasket plug in a tapered hole might change the reach when it bottoms out compared to a tapered hole with tapered plug or gasket style hole with gasket style plug.

 

I'm gonna e-mail Lloyd a link to this thread...hopefully he can chime in.

 

I believe the advantage is that those plugs have a recessed tip which is supposed to reduce detonation and let you run more timing.

 

Got a response from Lloyd...

 

This is from NGK.com web site.... Not much info.....

racing plug, 14mm, 3/4" reach, 5/8" hex, gasket seat, non resistor, V-power (v-grooved center electrode)

NGK - R-5671-A7
Automotive Fitting:
We do not have an automotive fitting for this part in our database.

As for www.ngksparkplugs.com the official site to late to call to find out any info...

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