What Cylinder Heads?
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What Cylinder Heads?

  1. #1
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    Default What Cylinder Heads?

    My brother is putting together a pair of 572 cui BBCs for his 30’ Scarab. The long block specs are:
    572 cui
    4.375 Stroke
    4.560 Bore
    Cam ≈.632 lift, 112 LSA, Roller (edit:I/E @.050 256/264)
    Planned Max RPM 5800
    1050 Dominator, (2 circuit)
    WP Merlin Marine single plane intake
    CMI exhaust headers
    Planned Compression Ratio 9.25:1 (based on stock Gen V 118cc heads) (He wants to run on Premium from the pumps.)
    30’ Scarab, twin TRS outdrives

    He runs in the James River, Hopewell, VA so he is in brackish water and but will likely run down to salt water in the Chesapeake Bay occasionally. The boat needs to stay family friendly. So considering the corrosion issue and all the performance tradeoffs, offer your opinions on the following:

    Should he run Cast Iron or Aluminum heads?
    What runner size?
    What Valve size?
    What brand has the best head for this application?

    There is a budget for the project, but his wife is not looking too close.

    Other cool engine info:
    Dart Big M block
    Bryant Crankshaft
    Callies Rods
    Diamond custom pistons, ceramic coated

    If ya want/need more info, let me know and I will ask my brother.
    Thanks
    Doug
    Last edited by Real McCoy; 10-28-2010 at 04:55 AM. Reason: add duration

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  3. #2
    cfm
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    I'd look to cast iron since:

    1) Weight vs aluminum is not going to slow that boat down at all. It's very heavy, and does not ride up on top of the water like the newer performance boats do.

    2) Corrosion issues. Sure, you can get hard anodized aluminum heads but they are much more costly and the main thing is that many heads are milled after anodizing, therefore the deck faces where the water flows thru can still do a number on them.

    That said, I'd look into the RHS 320 cyl heads.

    ================================

    Optimum for performance without custom porting and going aluminum Probably 315 AFR's if you can swing it or AFR325's if not. Of course Pro 1 's are good to.

    Note: head size mentioned above is going by your engine info and what I believe him to have for a cam.

  4. #3
    Senior Member EdonShano's Avatar
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    Quote Originally Posted by Real McCoy View Post
    My brother is putting together a pair of 572 cui BBCs for his 30’ Scarab. The long block specs are:
    572 cui
    4.375 Stroke
    4.560 Bore
    Cam ≈.632 lift, 112 LSA, Roller (I don’t have duration in my notes)
    Planned Max RPM 5800
    1050 Dominator, (2 circuit)
    WP Merlin Marine single plane intake
    CMI exhaust headers
    Planned Compression Ratio 9.25:1 (based on stock Gen V 118cc heads) (He wants to run on Premium from the pumps.)
    30’ Scarab, twin TRS outdrives

    He runs in the James River, Hopewell, VA so he is in brackish water and but will likely run down to salt water in the Chesapeake Bay occasionally. The boat needs to stay family friendly. So considering the corrosion issue and all the performance tradeoffs, offer your opinions on the following:

    Should he run Cast Iron or Aluminum heads?
    What runner size?
    What Valve size?
    What brand has the best head for this application?

    There is a budget for the project, but his wife is not looking too close.

    Other cool engine info:
    Dart Big M block
    Bryant Crankshaft
    Callies Rods
    Diamond custom pistons, ceramic coated

    If ya want/need more info, let me know and I will ask my brother.
    Thanks
    Doug
    I'm gonna run about the same combo but a little more compression..I got STEELCOMP working on my CANFIELD HEADS..hopefully will be done by next month..Plans are to start assembly of the motor right after the NHRA finals..I'll get Scott to post some numbers when he gets a chance..(I bet he's in the garage right now massaging some ports right now..)
    Formally know as UNFORGIVEN...

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  6. #4
    Just another Wannabe Wannabe's Avatar
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    When the desired rpm max is that low, don't jump on the trick heads with the huge numbers that you read in the National Dragster. A good solid deal with smaller runners that have good flow and velocity are going to be better in the long run.
    I like the RHS Iron idea myself. I prefer doing a touch of work to some of the older Merlin's, but those are hard to tell if they have not been abused. So just get a good RHS or similar and get durability.

  7. #5
    steelcomp was here
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    Ditto what wannabe said. I think there's a set of Merlin iron ovals in the spam section. Believe it or not, they'd probably work fine. With a little grinder work, they'd be killer even with a 2.25 valve. If they have a 2.300, even better.
    Last edited by scott foxwell; 10-27-2010 at 10:47 PM.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

  8. #6
    cfm
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    Quote Originally Posted by steelcomp View Post
    Ditto what wannabe said. I think there's a set of Merlin iron ovals in the spam section. Believe it or not, they'd probably work fine. With a little grinder work, they'd be killer even with a 2.25 valve. If they have a 2.300, even better.
    Merlin iron ovals on a 572 ? confused:

    572 cui
    4.375 Stroke
    4.560 Bore
    Dart Big M block
    Bryant Crankshaft
    Callies Rods
    Diamond custom pistons, ceramic coated
    Cam ≈.632 lift, 112 LSA, Roller (I don’t have duration in my notes)
    Planned Max RPM 5800
    1050 Dominator, (2 circuit)
    WP Merlin Marine single plane intake
    CMI exhaust headers
    Planned Compression Ratio 9.25:1 (based on stock Gen V 118cc heads) (He wants to run on Premium from the pumps.
    All this money on big cid's and good equipment edit in: twin engines edit end: and Merlin Oval Port's ?

    Never seen it done before. Have you seen any dyno sheets or even performance reports of someone else ever doing this ?

    Steel, IMHO it makes no sense to me.
    Last edited by cfm; 10-28-2010 at 03:42 AM. Reason: edit show: twin engines

  9. #7
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    I'd recommend a set of Dart 320's to 345's. Got a customer with a set of old Bull Dogs punched out to 4.600" bore with ported 990's and hyd roller cams. Engines have about 300 hours on them with hyd rollers. They made 680HP and pushed his Active Thunder in the 90's.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

  10. #8
    steelcomp was here
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    Quote Originally Posted by cfm View Post
    Merlin iron ovals on a 572 ? confused:



    All this money on big cid's and good equipment edit in: twin engines edit end: and Merlin Oval Port's ?

    Never seen it done before. Have you seen any dyno sheets or even performance reports of someone else ever doing this ?

    Steel, IMHO it makes no sense to me.
    I'm not surprised. Same reason VP can make 700hp with iron GM ovals on a 496. Port area and valve size.
    What do you come up with for a port area and valve size for that engine? You're an airflow expert...surely you can figure that out.
    Last edited by scott foxwell; 10-28-2010 at 08:34 AM.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

  11. #9
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    Steel,
    How many sets of RHS did it take to get 1 good set of heads that could be used?
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

  12. #10
    steelcomp was here
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    Quote Originally Posted by cstraub View Post
    Steel,
    How many sets of RHS did it take to get 1 good set of heads that could be used?
    LOL...twice as many as it shoud have.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

  13. #11
    Senior Member TNYoungblood's Avatar
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    Break time is over, Now get back to work Steel

  14. #12
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    Quote Originally Posted by TNYoungblood View Post
    Break time is over, Now get back to work Steel
    So the 540 is going to the dyno with Steels Heads and my camshaft. I better get out my good set of darts to "pick" the cam.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

  15. #13
    Senior Member TNYoungblood's Avatar
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    Quote Originally Posted by cstraub View Post
    So the 540 is going to the dyno with Steels Heads and my camshaft. I better get out my good set of darts to "pick" the cam.

    We was shootin for 800 and said the hell with that we goin for 850 ...

  16. #14
    steelcomp was here
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    Quote Originally Posted by cstraub View Post
    So the 540 is going to the dyno with Steels Heads and my camshaft. I better get out my good set of darts to "pick" the cam.
    Yeah, and give that dart board a good spin...

    Hey Mike, give me a call when you get a chance.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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