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Discussion Starter #1
I just finished putting my 460 back together after bending a valve (machine shop said I had a tight valve guide - bummer). The motor is a marine 460 from the mid-80's. Lower end is all stock with flat top pistons with duel valve relief grooves. Heads are 75cc Edlebrock Performer RPM CJs, Intake is Edlebrock Performer CJ, 800cfm Edlebrock carb, full MSD ignition/distributor/coil, and lightning through transom wet headers.

The machine shop (Bailey's in Mesa, AZ) estimated my compression ratio at 9.5:1. I run 91 octane in the motor. The boat is a 21' kachina with a Berkley pump.

What plug should put in the motor? It had ACDelco #5 plugs in it, but I was told that might be too hot of a plug to run in a jet boat.
 

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I just finished putting my 460 back together after bending a valve (machine shop said I had a tight valve guide - bummer). The motor is a marine 460 from the mid-80's. Lower end is all stock with flat top pistons with duel valve relief grooves. Heads are 75cc Edlebrock Performer RPM CJs, Intake is Edlebrock Performer CJ, 800cfm Edlebrock carb, full MSD ignition/distributor/coil, and lightning through transom wet headers.

The machine shop (Bailey's in Mesa, AZ) estimated my compression ratio at 9.5:1. I run 91 octane in the motor. The boat is a 21' kachina with a Berkley pump.

What plug should put in the motor? It had ACDelco #5 plugs in it, but I was told that might be too hot of a plug to run in a jet boat.
Cant tell if your whole system is MSD but MSD says .040 to .045 up to 10.50 to 1 N/A
 

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Discussion Starter #5
Would a Autolite AR135 work well?

Well now I'm even more confused. My marine mechanic told me to use the AR135 plugs. Those plugs have a tapered seat and a .460 reach. But then I checked the recommened plugs on summit for the Edlebrock heads and they suggest an Autolite 3926, which has a compression seat and a .750 reach.
 

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The ELD Heads take a 14mm gasketed .750 reach plug, Edelbrock recommends Champion rc12yc but i've always had good luck with autolite 3924s.

Good info here!! Are the Accel plugs any good for his set up, or even a stock set ogf heads?
I have ran them on all of my other motors with out an issue!!
:)hand
 
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