Someone recommended the NGK ZFR5N plug with gasket removed. The Bosch 4218 plugs are a taper fit. The Bosch was looked up at one of the local part stores. ( They maybe wrong) Are you saying you can remove the gasket on the NGK plug and get it to seal in a taper fit hole. I don't think this in correct.
Is my 67 head a taper fit or gasket fit type. I do have plug tubes.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

The taper fit plugs came in later years. I don't know when it began, but my son's '74 has the "drool" tubes, so it was after that.

Jerry

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There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

This chart shows the plug and other head changes.
http://www.slantsix.org/articles/parts-matrix/jpg.htm

Also, read this thread:
http://www.slantsix.org/forum/viewtopic ... tolite+985

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"When you find a big kettle of crazy, it's best not to stir it." - Pointy-haired Boss

1964 Valiant V200, 225/Pushbutton 904
BBD, CAI, HEI, LBP, AC, AM/FM/USB, EIEIO

The cut off year is 1974, 75 and up use the taper seat and can't use the 985's or ZFR5n's . I had a 2.5L ram van that I managed to find Pontiac spark plugs that fit that had a longer head so there might be something else out there for later heads.

I used the ZFR5N plugs. These are the plugs that where removed. (Autolite platuim) #2 and #6 look a bit different than the others. This motor has either 22,000 miles or 122,000 miles. (odometer rollover?) Your thoughts on the plugs.
http://www.renaissanceracing.com/images ... gsfull.JPG

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Oh and where do I get new plug tube O-rings?

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Fel-pro ES12794

Autozone

Got mine @ a year ago

Looks like your engine is running a little on the lean side. What is your timing set at? They are supposed to be a light tan color.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

have not checked timing. I have noticed a ping around 60 - 70 mph under light acel, but goes away as more gas is given. Running a 185 degree thermostat.

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir