I took the advice given by several and purchased NGKZFR5N plugs for my '63 Valiant. I removed the ring as mentioned but they wont tighten. I can insert them all the in but they just keep spinning around. Any ideas.

Woops! I've never replied to my own message but now I realize this plug requires a smaller socket.

Yup, you need a 5/8" spark plug socket for these, rather than the larger 13/16" socket you used to remove the old plugs.

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Too many people who were born on third base actually believe they've hit a triple.

What does continue to spin around are the tubes which might cause oil to leak. Doubling up on the O rings might provide for a snugger fit. I don't notice any difference in performance with these plugs.

You will notice more difference under marginal conditions such as warm up, cold weather, bad gas etc. I suspect you could run the carb leaner and still get good, even combustion with these plugs. It is my understanding they were designed for use with the lean burn engines of the 80's.
Sam

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If the tubes still spin with new O-rings and plugs then one of the following is happening:
- The bottom of the tube is worn or distorted, the tube(s) should be replaced.
- There is carbon build-up in the bottom threads of the spark plug hole, this prevents the plugs / tube assembly from fully seating and compressing the O-rings
Dd

Doubling up on the spark plug tube seals (O-rings) is not a good idea; don't do it.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Then what is the solution? This problem did not exist with the old style plugs.

Install 'em properly and everything'll be fine.

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Too many people who were born on third base actually believe they've hit a triple.

Speaking of these Plugs, If one decides to Jump to the above Mentioned NGK's Can the Gap be increased if nothng else is changed?? Same coil, dist etc? Greg

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I don't recommend it, no. Plug gap is mostly contingent on the ignition components you're running.

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Too many people who were born on third base actually believe they've hit a triple.

My guess is that you have carbon build-up in the bottom of the threads.
Carefully run a 14mm tap thru each spark plug hole to clean-out the carbon. Put some grease on the tap to catch and hold any dislodged crud.
DD

Instead of a tap use a spark plug thread chaser - like this one. Like a tap but the edges not as sharp so you won't loose any metal but still effectively cleans. Same deal, put a coat of grease on it.

I've used that one myself. Like it since you can put an extension right on it. Hint, take the tube out while using it. It is long enough to reach the bottom of the threads before bottoming out. Napa has them.

Using an HEI built from this group, and the NGK ZFR5N plugs, being questioned that this plug is wrong on slant 6 group on Facebook...have I got the right plugs?..having no issues but now wondering..1973 dart sport, Holley 390, moderate cam, heads shaved a thou, larger valves.
Thanks

THe slant six facebook group is full of wrong information. Don't listen to it. Young enthusiastic people who haven't spent the time to get familiar with the engine and the upgrades possible. This ebsite is a much better source of info. NGK ZFR5N ar the correct upgrade plug on a slant with spark plug tubes in the head.