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  1. #1
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    aluminum heads for boost?

    whats a better head for boost? aluminum or cast?

  2. #2
    Member scjeep4.7HO's Avatar
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    They both has their pluses and minuses but for us, the Aluminum will be aftermarket and be better right out of the box.
    Big ASS supercharged 4.7L HO, cammed, Custom Made Supercharger COG drive system, 72mm F&B throttle body, ROSS ceramic coated pistons, Billet H beam rods, 1st set of race prepped big valves heads W/ behive springs, Custom one off sheet metal intake, Modified Edelbrock Mustang intake elbow, ATI super dampner, 3,000 Edge racing billet stall converter, meth injected, SCT tuned, 39# injectors, 2 bar map, Turbo Smart Race Port BOV, 180* T stat, True dual exhuast, Built tranny W/ deep trans pan, built transfer case, 275 60 R17 rubber.

  3. #3
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    Dissipates the heat better too & so will allow you to bump your CR by about a point (eg: 8.5 - 9.5) but cant remember what stock CR is :-(

  4. #4
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    Stock CR is about 9:1 (sources vary between 8.7:1, 8.9:1 and 9.1:1). Keep in mind, the Edelbrock heads have a 58mm chamber, compared to the stock 62mm, so they'll bump compression a bit on their own. Generally, you don't want too much compression for boost, as it makes it harder to make lots of power without pinging.
    1998 ZJ 5.9 Limited - Deep Slate
    Mods: Big trans cooler, 231 swap, Indy 2.02 heads prepped by IMM, Comp 20-744-9 cam, 1.7 HS roller rockers, 52mm TB, Airgap manifold, DT headers and full 3" exhaust, SCT tune homebrewed by me, Martin Saine valve body, B&M tranny pan, magic suspension made from unicorn tears, power steering cooler, lots of lighting mods

  5. #5
    Member NoTime's Avatar
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    I have the Edelbrock heads on my boosted Jeep,, it also allows you a few more degrees possible for ignition advance ( but be carefull )

    I have mine with 62mm chambers to keep my compression down for the boost.
    1998 ZJ 5.9 Platinum - 408 SC Sleeper ( 7.49 / 11.? )
    2012 RAM - Tow Vehicle
    2007 GC SRT8 Daily Driver
    2003 TJ Rubicon Inca Gold - Trail blaster
    1973 Trumph GT6 MK III
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  6. #6
    Member syva4's Avatar
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    NoTime, where to buy Edelbrock aluminum heads with 62 cc?

  7. #7
    Member scjeep4.7HO's Avatar
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    I'm sure there are plenty of places to get the Eldebrock heads but summit racing or Jegs would be a good place to start.
    Big ASS supercharged 4.7L HO, cammed, Custom Made Supercharger COG drive system, 72mm F&B throttle body, ROSS ceramic coated pistons, Billet H beam rods, 1st set of race prepped big valves heads W/ behive springs, Custom one off sheet metal intake, Modified Edelbrock Mustang intake elbow, ATI super dampner, 3,000 Edge racing billet stall converter, meth injected, SCT tuned, 39# injectors, 2 bar map, Turbo Smart Race Port BOV, 180* T stat, True dual exhuast, Built tranny W/ deep trans pan, built transfer case, 275 60 R17 rubber.

  8. #8
    Member NoTime's Avatar
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    Quote Originally Posted by syva4 View Post
    NoTime, where to buy Edelbrock aluminum heads with 62 cc?
    I had mine modified to 62 mm chambers by machine shop. ( at least that's what my engine builder said )
    1998 ZJ 5.9 Platinum - 408 SC Sleeper ( 7.49 / 11.? )
    2012 RAM - Tow Vehicle
    2007 GC SRT8 Daily Driver
    2003 TJ Rubicon Inca Gold - Trail blaster
    1973 Trumph GT6 MK III
    20 Ft Enclosed Car Hauler

  9. #9
    Member syva4's Avatar
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    NoTime, Where make? Price for make?

  10. #10
    Member syva4's Avatar
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    Open CC on Edelbrock heads up to 64cc price $325.00 on Hughesengines.
    Last edited by syva4; 06-30-2012 at 04:57 PM.

  11. #11
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    This is an old discussion... but something I'm looking at now. There's a reason Edelbrock made their chambers smaller than stock on their aluminum heads: because of the much better heat dissipation of aluminum they are more resistant to detonation at higher C/R's. In fact, when Mopar made their own aluminum heads they were 5cc's smaller than Eddie's 58cc's, at 53cc's, and it was for the same reason - they were able to raise C/R a significant amount without detonation.
    Aluminum dissipates heat 4 times faster than iron!! - so aluminum hot spots don't stay hot. That's why you need a TIG welder for aluminum, even though aluminum melts at about half the temp of iron.
    So, in a boosted application when the effective C/R is increased, aluminum heads are definitely better for preventing detonation. Enlarging the combustion chambers from 58cc a little is also a good idea, though not necessary, depending on how much boost you're running. It's probably enough just to smooth the combustion chamber surfaces, which might only increase the volume by 1 or 2 cc's, but the smoothing also eliminates hot spots that are a cause of detonation - and you don't need to pay Hughes $325 for that.
    Unless you're running extreme boost, there's no reason to get below the stock C/R (or even down to the stock C/R) with aluminum heads. Keeping the C/R up a bit would give better low-end driveability before boost kicks in, so it's best not to go larger than needed for a street Jeep.

    When I get around to doing the heads and cam for my supercharger, I'll do all the effective C/R calculations, and dial in the combustion chamber volumes to optimize how I actually run it - but the heads will certainly be aluminum.

    Ideal would be to zero-deck the block and enlarge the aluminum combustion chambers to make up the difference to increase quench, but maintain a good C/R...
    Last edited by carlmon; 08-14-2015 at 11:29 PM.

  12. #12
    SCT Tuning Guru
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    Eddys aren't 58cc.
    Always outmanned...Never outgunned

  13. #13
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    Quote Originally Posted by FlyinRyan View Post
    Eddys aren't 58cc.
    Are you thinking of some other Edelbrock head, or are you saying their published specs are incorrect? Because these are the Edelbrock heads recommended for hydraulic roller lifter Magnum V8 specs straight from their website (part# 61775):
    Performer RPM Cylinder Heads For Chrysler Magnum
    Cylinder Head Specifications:
    Combustion chamber volume: 58cc
    Intake runner volume: 176cc
    Exhaust runner volume: 75cc
    Intake valve diameter: 2.02"
    Exhaust valve diameter: 1.60"
    Valve stem diameter: 11/32"
    Valve guides: Manganese bronze
    Deck thickness: 5/8"
    Valve spring diameter: 1.46"
    Valve spring maximum lift: .580"
    Rocker stud: 3/8"
    Guideplate: Hardended steel
    Pushrod diameter: 5/16"
    Valve angle: 18
    Exhaust port location: Stock
    Spark plug fitment: 14mm x 3/4 reach, gasket seat


    Also, the specs on the Mopar branded Magnum heads made by Edelbrock are the same (whether they're still available is unknown):

    Aluminum Magnum Cylinder Heads


    * Designed for 1992 and later 5.2L (318) and 1993 and later 5.9L (360) Magnum.
    * Stock Magnum intake / exhaust flange and port locations
    * 58cc Chambers
    * 2.02" Stainless Intake valves
    * 1.60" Stainless Exhaust valves
    * General performance valve springs
    * Steel 7-degree retainers
    * Bronze valve guides
    * Viton valve seals
    * Hardened valve seats with 5-angle valve job
    * 176cc Intake ports
    * 75cc exhaust ports
    * Requires Mopar Hardened Pushrod set
    * Requires Mopar Adjustable Roller Rocker Arm Set P5153852
    * For use with camshafts up to .580" lift
    P5153847 Aluminum Magnum Cylinder Heads 836.00 each

  14. #14
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    Update on this thread:
    Icon as of this year makes a 34cc step dish forged piston specifically for 408 stroked and supercharged Magnum engines, P/N IC982. 27cc pistons used to be the deepest dish off the shelf pistons for our motors - with 27cc pistons 9.76:1 was the lowest compression possible with 040 quench, without serious work on the head chambers.
    With the Edelbrock aluminum heads with 2cc's of smoothing (final 60cc head chambers), these pistons with 1.445 compression height and that large dish means it's easy to zero deck and end up at 9.16:1 static C/R and .040 quench height (with .040 gaskets) without custom pistons on a 408 build.
    Cometic makes Magnum head gaskets in 040, 036, 030, and 027, so it's really easy to compensate for any variation of the final deck height, or to bump the c/r a bit.
    Last edited by carlmon; 05-18-2016 at 08:33 AM.

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