Comp xtreme marine cam??
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Comp xtreme marine cam??

  1. #1
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    Default Comp xtreme marine cam??

    Hi new to the forum here. I am building A gen 6 stroker 489 ci. I was looking at a comp xm284hr cam. (here are the specs: http://www.compcams.com/Cam_Specs/Ca...?csid=596&sb=2 ) My questions are will I have a problem with reversion using stock exhaust, will the idle be OK for shifting a bravo drive, and could I use my stock roller lifters. Thanks

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    If you haven't seen it already, check out Dennis Moore's book. Lots of good, practical info.

    http://www.amazon.com/Big-Block-Chev.../dp/1557882975
    Last edited by muskwa; 10-27-2009 at 07:59 PM. Reason: punctuation

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    Quote Originally Posted by rcarroll View Post
    Hi new to the forum here. I am building A gen 6 stroker 489 ci. I was looking at a comp xm284hr cam. (here are the specs: http://www.compcams.com/Cam_Specs/Ca...?csid=596&sb=2 ) My questions are will I have a problem with reversion using stock exhaust, will the idle be OK for shifting a bravo drive, and could I use my stock roller lifters. Thanks

    Wrong profile for an I/O in my personal opinion. You need to keep the lobe separation at or over 112* for stock type exhaust...

    How hard do you want this thing to run?

    Headers would be required to run that jetboat bumpstick....

    If I may be so bold, if you want to run a Comp XM, check this one...
    I believe the stock rollers will work fine.

    http://www.compcams.com/Cam_Specs/Ca...?csid=595&sb=2

    Good lobe centers and will work in your aplication, not saying it's the right choice for your combo, but the stock exhaust is your Achilles heel IMO.

    Check into some IMCO or Eddie, or Kodiak exhaust...There are several exhaust systems out there that will outperform the snot out of the "Old Iron's"
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    Thanks for your help the xm270 was my second choice. I want to stay around 4900-5300 rpm. Is there any aftermarket exhaust that will work with the silent choice switchable exhaust.

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    Senior Member GT Jets's Avatar
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    Quote Originally Posted by rcarroll View Post
    Thanks for your help the xm270 was my second choice. I want to stay around 4900-5300 rpm. Is there any aftermarket exhaust that will work with the silent choice switchable exhaust.
    We have IMCO's on our 330HP Bravo I and the exhaust goes thru transom, I think if you check their catalog it will show what will and wont work...You need the manifolds and the risers for the systems to work (won't bolt up)..Made a noticable difference all by themselves...

    GT
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    I'm running a Comp 1-456-8 on EMI Thunders. no reversion

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    how is the idle with that cam. I will most likely be upgrading my exhaust what is the most bang for the buck system out there ?

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    Quote Originally Posted by GT Jets View Post
    Wrong profile for an I/O in my personal opinion. You need to keep the lobe separation at or over 112* for stock type exhaust...

    How hard do you want this thing to run?

    Headers would be required to run that jetboat bumpstick....

    If I may be so bold, if you want to run a Comp XM, check this one...
    I believe the stock rollers will work fine.

    http://www.compcams.com/Cam_Specs/Ca...?csid=595&sb=2

    Good lobe centers and will work in your aplication, not saying it's the right choice for your combo, but the stock exhaust is your Achilles heel IMO.

    Check into some IMCO or Eddie, or Kodiak exhaust...There are several exhaust systems out there that will outperform the snot out of the "Old Iron's"
    HIS CAM and YOUR CAM are BOTH on 112 lobe centers. Your choice is just smaller so it will run a little smoother down low. Your cam choice will work OK, but it's not enough (IMHO) for a large port motor. (of that larger cubic inch) YES ! The STOCK MANIFOLD exhaust backpressures will be the killer. Don't worry about reversion if the motor idles UNDER 900 RPMs.

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    Senior Member GT Jets's Avatar
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    Quote Originally Posted by GFINISHLINE View Post
    HIS CAM and YOUR CAM are BOTH on 112 lobe centers. Your choice is just smaller so it will run a little smoother down low. Your cam choice will work OK, but it's not enough (IMHO) for a large port motor. (of that larger cubic inch) YES ! The STOCK MANIFOLD exhaust backpressures will be the killer. Don't worry about reversion if the motor idles UNDER 900 RPMs.
    I was not reffering to a reversion issue, I was refferring to not having the exhaust system with his current configuration to get the most out of that cam package At 5200 RPM he is not taking full advantage of the port sizes anyway, so a smaller profile camshaft will pay dividends with an I/O...

    Ultimately, bigger cam, better exhaust, and higher gear ratio, but....I'm not made of money, and have not figured out how to crap any...




    GT

    edit;, most "marine cams" will have a 112* center...
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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