Spark plug advice

[Bbody4speed]

Looking for spark plug advice for my mild 440 9.5 :1 compression, mild cam. It has 452 heads. I am hearing that the champion RJ 10's are no longer available. Looking for an a equivalent in another brand. Any help would be appreciated. Thanks.

 

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Type "spark plug" in the search window. We've been round and round a 100 times on this...

 

[Outsider]

10s seem like a pretty cool plug that compression ratio. I run 10s on motors with compression a couple points higher, and 12s with around your indicated compression.

 

[Aron Gleason]

Maybe try a ngk heat range 4 plug or a 5.

 

[pnora]

What 452 heads? Some are gasket seat plugs and some are taper seat.

 

[Bbody4speed]

What 452 heads? Some are gasket seat plugs and some are taper seat.

Gasket seat, I believe.

 

[Bbody4speed]

10s seem like a pretty cool plug that compression ratio. I run 10s on motors with compression a couple points higher, and 12s with around your indicated compression.

Thanks, that is the kind of advice I'm looking for.

 

[Bbody4speed]

Maybe try a ngk heat range 4 plug or a 5.

Do you know the whole part number?

 

[4speed68rt]

Champion RJ12YC

 

[Aron Gleason]

Do you know the whole part number?

3332 or xr5

 

[Geoff 2]

NGK BP5S is what you need.

 

[RemCharger]

3332 or xr5

Yup ^^^

 

[Bbody4speed]

Champion RJ12YC

Are they still available?

 

[Dennis H]

NGK’s.

 

[lewtot184]

i've used all brands and types of spark plugs in iron heads through the decades. my best advice is ignore the name on the plug and just look for something that has the correct tip and heat range. if you use a 14mm/3/8" reach/ projected tip then there will be several that will do the job. i believe the easiest to obtain is the autolite 85. i've used ngk's without problems, champions, motorcraft, etc thru the years and the only plug i thought was dismal was the champion rj12y. my favorites would be champion j11y and j13y but they haven't been made for decades. another factor to look at is the need for a resistance plug. if you're using some type of electronic ignition some resistance in the plug/wire combo can be a plus. i do ohm test my plugs and the new champions seem to be the worst on resistance. the spark plug is just a "piece" of the tune. keep in mind several other factors will determine the success of your plug choice. no one "piece" by itself can cure a bad tune-up.

 

[4speed68rt]

Are they still available?

O'reillys has them.