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#2436711 - 01/18/18 12:06 AM spark plugs ?
sixbbl 69 Offline
member

Registered: 04/26/16
Posts: 27
Loc: Illinois
69 440 six bbl with mopar performance alum heads.525 hp pump gas. what type and number plug should i start with for first start up.

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#2436712 - 01/18/18 12:07 AM Re: spark plugs ? [Re: sixbbl 69]
A/MP Offline
mopar

Registered: 10/09/08
Posts: 688
Loc: East Coast
stock '69 440+6 plugs

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#2436714 - 01/18/18 12:11 AM Re: spark plugs ? [Re: A/MP]
sixbbl 69 Offline
member

Registered: 04/26/16
Posts: 27
Loc: Illinois
J11Y won't fit the heads.

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#2436719 - 01/18/18 12:48 AM Re: spark plugs ? [Re: sixbbl 69]
madscientist Online   content


Registered: 09/17/14
Posts: 2134
Loc: Washington
RC9YC champion

Use a 12 if it's under 10:1
_________________________
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston

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#2436911 - 01/18/18 01:20 PM Re: spark plugs ? [Re: sixbbl 69]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 31079
Loc: Bend,OR USA
Do you know the compression ratio and octane rating you will use?
I have a 505 C.I. 440 block that has right at 10.08 to 1 compression and I'm going to use Champion RC12YC on our local pump swill. I've had other pump gas motors with a little more compression, 10.78 to 1, that I used champion RC9YC and Autolite AR3911 non resistor race plugs and AR3910 non resistor race plugin them with good results up
I went out to the shop and got couple of other Autolite resitor street pump gas plugs, 3924 and maybe 3925, which is hotter, if they make that plug number now scope
Good luck, let us know what you use and your results scope


Edited by Cab_Burge (01/18/18 05:18 PM)
_________________________
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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#2437750 - 01/19/18 09:08 PM Re: spark plugs ? [Re: sixbbl 69]
sixbbl 69 Offline
member

Registered: 04/26/16
Posts: 27
Loc: Illinois
thanks Mad and Cab

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