can i get close to 800 hp with 572-9.8-1 comp
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can i get close to 800 hp with 572-9.8-1 comp

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    Senior Member badbug3's Avatar
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    Default can i get close to 800 hp with 572-9.8-1 comp

    i have a 10.2 block with 4.5 bore and will be using a 4.5 stroke with a 6.7 rod and need a set of heads that would make the most hp i can on 9.8-1 comp and pump gas for an inboard outboard bbc. Going in new 24 ft htm ss. Should i try the brodix oval port 332 cc head . Max rpm is 6000 with a hydraulic roller cam and dominator carb. Low speed torque will be very important with this boat as im sure it will have a 28 pitch prop on it.


    which head do u think would be the best overall head and what cam?

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    Resident Ford Nut Sleeper CP's Avatar
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    Quote Originally Posted by badbug3 View Post
    Max rpm is 6000 with a hydraulic roller cam and dominator carb.


    which head do u think would be the best overall head and what cam?
    The 6,000 rpms max and hydraulic roller will be your limitation. My 10.8:1 565 made 855 at 6,600 with very good heads and a mechanical roller.

    You'll get close to it with the right combo.

    Sleeper CP

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    steelcomp was here
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    Quote Originally Posted by badbug3 View Post
    i have a 10.2 block with 4.5 bore and will be using a 4.5 stroke with a 6.7 rod and need a set of heads that would make the most hp i can on 9.8-1 comp and pump gas for an inboard outboard bbc. Going in new 24 ft htm ss. Should i try the brodix oval port 332 cc head . Max rpm is 6000 with a hydraulic roller cam and dominator carb. Low speed torque will be very important with this boat as im sure it will have a 28 pitch prop on it.


    which head do u think would be the best overall head and what cam?
    If you don't have heads, how do you know your compression?
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

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    Quote Originally Posted by steelcomp View Post
    If you don't have heads, how do you know your compression?
    i agree with steelbut im a big fan of brodix as i live 45 miles from themcall them and ask.good luck travis

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    Senior Member Brendellajet's Avatar
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    Quote Originally Posted by steelcomp View Post
    If you don't have heads, how do you know your compression?
    He is targeting the mentioned compression ratio.

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    isn't the basic crate 572 around that compression and making almost a 150hp less than his target hp? gonna take some cam/head combo magic to make it happen.

    Dare to be different, if it turns out great you can claim you planned it that way.

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    Senior Member badbug3's Avatar
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    Quote Originally Posted by Brendellajet View Post
    He is targeting the mentioned compression ratio.
    thanks brendellajet,

    9.8 or thereabout compression ratio for the larger boat and load it will see. I think that boat is a real efficient hull and not really all that heavy according to what i hear. Anyway thats why im asking for info on this build and especially wondering if anyone has run the brodix oval port heads and had anything good to report about them. If rpm was kept at 6000 or below, would there be more hp with solid roller or not? thanks

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    Senior Member Futs's Avatar
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    Quote Originally Posted by badbug3 View Post
    thanks brendellajet,

    9.8 or thereabout compression ratio for the larger boat and load it will see. I think that boat is a real efficient hull and not really all that heavy according to what i hear. Anyway thats why im asking for info on this build and especially wondering if anyone has run the brodix oval port heads and had anything good to report about them. If rpm was kept at 6000 or below, would there be more hp with solid roller or not? thanks
    Why not just get stock shelf pistons that are 10.2: with any 119cc chamber and then get a nice cam ground to match the whole package. Not saying 9.8 pistons arnt stock, but your real safe with aluiminum heads at the compression ratio. You target would be met for sure. Is your drive built for the power?

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    Senior Member MACHINEHEAD1's Avatar
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    Search one of the old threads. The title is 800N/A on pump gas. Many combos there. Myself, BD and CFM have the outdrive combos. Very good thread with plenty of chit talking.

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    Quote Originally Posted by badbug3 View Post
    thanks brendellajet,

    9.8 or thereabout compression ratio for the larger boat and load it will see. I think that boat is a real efficient hull and not really all that heavy according to what i hear. Anyway thats why im asking for info on this build and especially wondering if anyone has run the brodix oval port heads and had anything good to report about them. If rpm was kept at 6000 or below, would there be more hp with solid roller or not? thanks
    There is almost always more hp with a solid roller...I would think about boring out to 4.60" to unshrould the valves and go with larger cc heads...A 572-598" is going to have plenty of TQ at the low end for a 24' cat no matter what you do...

    800hp will be tough IMO with the combo you mentioned, but you should get 750 pretty easily.

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    cfm
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    Quote Originally Posted by cjordan View Post
    A 572-598" is going to have plenty of TQ at the low end for a 24' cat no matter what you do...

    800hp will be tough IMO with the combo you mentioned, but you should get 750 pretty easily.
    I agree. A Merc 6.2MPI will even get that boat on plane no problem.

    I also agree with the HP vs HR vs RPM statement you (Cjordan) made. Achieving a real 800hp would be an 'A' Game effort with a HR and limiting yourself to 6k. Okay, it would still need some more rpm's. Maybe more compression and an extra carb could just get you there.

    With a small cat and that cid engine, I'd put the concentration of effort towards making as much power as you can from somehwere between 4500-5000rpm and then up to redline.

    If you really want that 800hp at or before 6k, you could go with low compression,basic heads and take the extra money and buy a basic blower.

    N/A you'll need to be at / or around 6300-6400 to nudge the true 800hp mark. With these rpm's I'd look at shaft rocker even if you stay with HR.

    Anyway, Rev that beatch and let'r air out. LOL.

    Sounds like a real fun project and toy. Good luck, have fun, and remember to play hard and play safe.
    Last edited by cfm; 03-05-2009 at 05:21 PM.

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    cfm
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    Quote Originally Posted by MACHINEHEAD1 View Post
    Search one of the old threads. The title is 800N/A on pump gas. Many combos there. Myself, BD and CFM have the outdrive combos. Very good thread with plenty of chit talking.
    Don't forget Ausbullet. He is the high rpm bravo man.
    I really didn't have anything good to add there as I don't live there (hp or rpm in a I/O) in a personal way like you, BD, Ausbullet, WetteVette, and Cjordan do.

    Here's the link:
    http://www.performanceboats.com//sho...ighlight=800hp

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    Quote Originally Posted by Sleeper CP View Post
    The 6,000 rpms max and hydraulic roller will be your limitation. My 10.8:1 565 made 855 at 6,600 with very good heads and a mechanical roller.

    You'll get close to it with the right combo.

    Sleeper CP
    FYI,

    Info on a 800 HP at 6,000 engine. Solid roller:



    S CP

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    Sleeper CP- NICE numbers on that 565! My 632" was a 10.5:1 with 2X775 demons. It made 900hp @6600. ~820 ft/# at ~5200. It liked 32 degrees as well. You were running a big cam in that motor. Do you remember the LSA? mine was a 280/288 @.050 .772" lift on a 115. Oh yeah, it wanted more cam as we kept retarding it and power went up...but we ended up running it +2....

    you had that puppy lean and mean!
    Last edited by cjordan; 03-05-2009 at 08:30 PM.

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