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yehaabill
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Group: Forum Members
Last Active: 9 Years Ago
Posts: 426,
Visits: 1.4K
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Y-Guys Just got my new YBM and WOW!!!! They have arrived(Heads) They look great but, the clearance around the plugs looks the same. Will this be enlarged to give the plug socket more room or is this the pre-production set? Can't wait to see flow results and dyno run.... Bill
Bill Pelham,Al
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Hoosier Hurricane
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Group: Moderators
Last Active: 37 minutes ago
Posts: 3.7K,
Visits: 321.5K
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Bill: I read that the heads would have 14 mm plugs, maybe it is intended to use the ones with a 5/8 hex, which would use a smaller socket. Don't worry, John will have it covered. Wish I had my mag, it isn't here yet. Maybe the postmaster is reading it. John in Selma, IN
John - "The Hoosier Hurricane"
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Glen Henderson
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Group: Forum Members
Last Active: 8 Years Ago
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The one complant I have with Bruce is the way he mails out the mag, Bill is 90 miles up the road from me and it seems he receives his issue a week or two before mine shows up. Can't wait for it to show up.
Glen Henderson
Freedom is not Free
Letohatchee, AL
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Teros292
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Group: Forum Members
Last Active: 2 Years Ago
Posts: 129,
Visits: 12.3K
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I got my YBM two days ago, it´s really getting fast to other side of world, but it is only about 7 or 8 hours flight from New York to Finland and couple of hours from Bruce to New York and half hour drive from Helsinki airport to me.
Tero from Nurmijarvi, Finland56 Country Sedan, 61 F-100, 61 F-600, 55 F-620, 52 Mercury
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Daniel Jessup
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Group: Forum Members
Last Active: 35 minutes ago
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I read the article about the heads in issue 88, but unless I missed, I did not see anything about the out of the box compression ratio. Anyone know?
Daniel JessupLancaster, California aka "The Hot Rod Reverend" check out the 1955 Ford Fairlane build at www.hotrodreverend.com
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charliemccraney
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Group: Moderators
Last Active: 19 minutes ago
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The compression ratio will vary from engine to engine. I think it said they have 59cc combustion chambers.
Lawrenceville, GA
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PF Arcand
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Group: Forum Members
Last Active: 8 Months Ago
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Daniel: As Charlie says, compression will vary with displacement. However, the best stock compression "G" heads have about 69cc chambers. Mummert is shooting for 60-64cc, a substantial improvement.
Paul
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Glen Henderson
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Group: Forum Members
Last Active: 8 Years Ago
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I talked to John yesterday, the set of heads that are pictured is the only set todate. He plans to cast two more sets next week and he is still shooting for early spring for release to the public. I suspect that it will require placing an order and then waiting for him to cast and machine a set due to the investment. I called him in Aug to buy one of the new intakes, he said they should be ready in Oct, but as of yesterday he did not have them ready. I think he has been spending all his time working on the heads. He said that he would try to have the intakes done in 3 to 4 weeks.
Glen Henderson
Freedom is not Free
Letohatchee, AL
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charliemccraney
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Group: Moderators
Last Active: 19 minutes ago
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Doing the math, it looks like it will raise the compression of a given engine by at least 1 point when compared to G heads. It will be a larger increase on larger engines. And potentially larger depending on the heads currently installed on that engine. The increase is necessary to make up for the heat lost due to aluminum's ability to dissipate heat more effectively than iron; heat lost is lost power, increasing compression gets it back.
Lawrenceville, GA
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PF Arcand
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Group: Forum Members
Last Active: 8 Months Ago
Posts: 3.3K,
Visits: 238.8K
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I can't put words in Mummert's mouth obviously, but I suspect in order to make the heads accessible to a wide cross section of customers, (and financially feasible) he has to keep the compression down somewhat. Not everyone is involved in racing or wanting to pay for premium gas everyday. For those seriously into competition, domed pistons may be necessary in some cases.
Paul
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