Re: NGK Plugs
 

Marlin,I changed from the ac delco to ngk on my restored 68 nova ss 396/350hp ,turbo 400 ;matching#car.The car had a slight miss;went away with the ngk.rob clary had mentioned to me that the ngk had a less chance of spark failure than the ac delco;dyno # proved it.chris Teed best et with F70 redline tires 13;28 with 3;42 gear

Re: NGK Plugs
 

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Hmmmm... so what's an NGK 'R5671A-8'?? A buddy thinks they will fit the Deuce?

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The difference is the seats (gasketed verses tapered)...the 5671 is for the 840s, the UR5 is for the 291.

Re: NGK Plugs
 

Since its an Olds, the numbers may not be the same. I am running V-power racing plugs # r5670-7. They have worked great and I did notice differences in how well it starts up and runs.