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Thread: 502 vs 502

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    502 vs 502

    I know about the older 454 / 7.4 / 502 engine family, with distributor ignition.

    Even today I see that MerCruiser offer a 502.
    What is that thing, from a technical standpoint?


  2. #2
    Platinum Member Platinum Member mike tkach's Avatar
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    according to mercury,s info that engine is 380 hp with a max rpm of 4800.it would be a good low hp engine,but its no hp 525.lol
    MIKE TKACH

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    Quote Originally Posted by mike tkach View Post
    according to mercury,s info that engine is 380 hp with a max rpm of 4800.it would be a good low hp engine,but its no hp 525.lol
    ........................
    Last edited by FIXX; 09-29-2013 at 11:54 PM.

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    VIP Member VIP Member MILD THUNDER's Avatar
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    They also have the HO version of that. 430HP. Looks like a modern version of the old 502MPI mag engine. I noticed it has 02' sensors in the manifolds, so probably a better EFI version that feedbacks the ecm. Wonder if it has the forged internals like the old mags?

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    Forum Regulator Sydwayz's Avatar
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    Well, it's not a 525EFI, because they are known to dyno somewhere between 535 and 560 HP right out of the factory

    Check out the new 502 520-HP *8.6L* version.
    http://www.mercuryracing.com/sterndrives/hp520.php
    http://www.mercuryracing.com/blog/loto-520/
    Mercury Racing Releases New 520 Engine

    Mercury has moved away from the 496 block and now offers 3 versions of the 502 plus the new 8.6L:

    8.1L Mag making 380 hp
    8.1L Mag H.O. making 420 hp
    And there is still the ever popular 525EFI.

    Mercury Racing 520 making 520 hp (Edited, this engine is 8.6L; not 8.2L, mah bad.)
    Last edited by Sydwayz; 09-30-2013 at 04:59 PM. Reason: corrected info, thanks mike tkach
    Brian @ activethunderboats . com

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    Platinum Member Platinum Member mike tkach's Avatar
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    Quote Originally Posted by Sydwayz View Post
    Well, it's not a 525EFI, because they are known to dyno somewhere between 535 and 560 HP right out of the factory

    Check out the new 502 520-HP version.
    http://www.mercuryracing.com/sterndrives/hp520.php
    http://www.mercuryracing.com/blog/loto-520/
    Mercury Racing Releases New 520 Engine

    Mercury has moved away from the 496 block and now offers 4 versions of the 502:

    8.1L Mag making 380 hp
    8.1L Mag H.O. making 420 hp
    Mercury Racing 520 making 520 hp
    And there is still the ever popular 525EFI.
    thats good information,but not the engine the op asked about and just fyi,the new 520 horse engine isnot a 502,but rather 523 cu in.
    MIKE TKACH

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    So the current 502s now offered are the same old big block GM base engine as the 454/7.4 and old 502?

  8. #8
    Platinum Member Platinum Member mike tkach's Avatar
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    not exactly,the 454 and 502 blocks are not the same,and gm is no longer producing them.i believe mercury bought the rites from gm for the 502 blocks,maybe others will have more information on this.
    MIKE TKACH

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    Quote Originally Posted by MILD THUNDER View Post
    They also have the HO version of that. 430HP. Looks like a modern version of the old 502MPI mag engine. I noticed it has 02' sensors in the manifolds, so probably a better EFI version that feedbacks the ecm. Wonder if it has the forged internals like the old mags?
    i read somewhere that the new 502 mag is 380 hp at the prop...the 430 number is at the crank..

  10. #10
    Forum Regulator Sydwayz's Avatar
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    Quote Originally Posted by mike tkach View Post
    thats good information,but not the engine the op asked about and just fyi,the new 520 horse engine isnot a 502,but rather 523 cu in.
    You are absolutely correct. I missed that in my first pass. I guess that speed reading class back in the day isn't good for much. Thanks for the correction & I have edited my post.
    Brian @ activethunderboats . com


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