dual plug heads.

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Apr 5, 2010 | 11:54 AM

#11

zaac

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Quote:

Originally Posted by misfitcj

correct the idea is they are "hemi" head. my shovel came that way. I will agree to the idea, just because they are there. otherwise I think the gain is really not noticable? to be a bit of an devils advocate. Any dyno's done on this? I am off to search for the info...

can't find a dyno sheet comparrison. However found some great disscussion here.

http://www.shovelhead.us/forum/showt...dual+plug+dyno

Never seen the actual dyno sheet but a few guys over at that site you mentioned claimed to have done a few dyno runs and actually lost a couple hp. If someone had a good set of 3 5/8 heads that weren't dual plugged I would trade them.

Apr 5, 2010 | 04:05 PM

#12

andremn

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From:

Thanks for the input. First off, this is not a discussion if it works or not. Maybe it does, maybe it dont. The issue i am trying to solve is to find a plug that will fit the 14 mm hole in the head and has a slim body like the little plugs on a new Harley. All the short reach like the Autolite Ap 65 has fat 13/16 hex and that will not fit the hole in the finns between the pushrods. The engine is a 1981 93" stroker and runs great, I just dont want to take the heads off to have the hole machined bigger to fit the fat body plugs. Thus I need a short reach slim body plug with 14nn thread.

Apr 5, 2010 | 04:16 PM

#13

zaac

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I use Champion RJ12YC for the short plug on the right side. RN12YC is long reach. You may be able to cross reference it on their site if you want an Autolite. I'll see what I can find.

Apr 5, 2010 | 04:31 PM

#14

zaac

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Sorry, I didn't read your post very good. Didn't notice 13/16 hex was too big. The RJ12YC is also 13/16. You may have trouble finding a 5/8 hex as they might all be plugs with the tapper seal rather than the gasket seat. I know Champion doesn't have one.

Last edited by zaac; Apr 5, 2010 at 04:37 PM.