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Hello. Newbie here. I've come across some spark plugs which I believe that I bought for my 68. They are Champion UJ-10Y plugs. Will these fit or is there a web link where I can potentially find the information?
 

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correct plugs

Those are plugs for your pontiac, but depending on how your engine is built.

thats a fairly cold plug

to keep it simple the number in this case the 10 tells how "cold a plug will run" most high comp motors and race motors need a cold plug to reduce pre-ignition in hotter more powerful engines.

hotter 14
hot 12
cold 10
colder 9

most "street" motors run on rc12 for instance.

i have a 12 to 1 500+ HP motor, i would use 9 (RC 9YCC )or likely a 10 (RC 10YCC )
 

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Discussion Starter #3
Correct plugs

Thank you for the prompt response. I found my ebay sheet with the description. It was: '1959-1968 Pontiac Champion Spark Plugs Royal Bobcat GTO'. Based on your response, being a colder plug would coincide with the Royal Bobcat claim-I guess. At least I know they will fit; how it runs will be another matter.
 

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The standard plug was a J12 in Champion (if you used Champion instead of AC). J11's and J10's were used by Royal Pontiac and others FOR STRIP USE. They're too cold for driving around on the street. They will fit, and they will work, but they'll tend to load up while idling around, etc.
 
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