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Thread: SBC 385 dyno results

  1. #1
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    SBC 385 dyno results

    Last season the 383 was dependable but lacked power. Gps mid 70's. Pulled engine and sent short block to machinist for freshening. Reset cam and bored block to .040 over, also replace bearings. Needed valve job ( valves hammered into seat), likely valve float. Mind you, only 30-35 hrs on eng.

    Dyno time arrived and did 12 pulls. The final pull advanced timing to 36* total and eng. came alive. Results below.

  2. #2
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    Wow! You must be pleased.

    Nice torque curve.
    “Oh right, because you walked into strippers discount warehouse and said ‘Help me showcase my intellect.’” - Archer

    Bill
    Grand Rapids, Michigan
    1985 Donzi Criterion SS
    1967 Donzi 16 Ski Sporter, C16-409, Has a new home!
    38' Carver Aft Cabin
    1968 Sea Ray SRV 180 w/1975 70 hp Evinrude
    10" RIB w/15 hp 1984 Evinrude

  3. #3
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    Awesome power from a 385! Care to share some of the specifics?
    Maddy's Daddy
    L.I.,N.Y.

  4. #4
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    Question

    Just curious, where would you set a rev-limiter on a motor like this?

    5500 with flattening HP and declining torque?
    5000 with slightly declining torque and increasing HP?
    4600 with max torque and increasing HP?
    Something else? What would be the factors you look at when making this determination?

    I would imagine, although you can get higher Hp with higher rpms, you consider longevity as part of the equation.

    Bob
    Member - WAFNC
    1997 22 Classic (sold)
    1997 Formula 271 Fastech
    502 Mag MPI

  5. #5
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    Nice T curve. What boat?
    Cheers,
    Pismo
    1996 22 Classic
    Red with Stainless Windshield
    Stock Gen VI 502 Magnum MPI-415hp
    Stock Bravo I
    25" Mirage Plus
    74.5mph best @ 5050rpm GPS (Speedo said 80)
    27" Labbed Mirage Plus
    75.5mph best @ 4800rpm GPS (Speedo said 82)

  6. #6
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    Thanks for the positive comments.
    Wow! That was the first word from my mouth also. The T curve was of utmost interest to me in the eng. build. Thanks to Bullet cam who chose cam to match the AFR heads.
    If I was to set a rev limiter I would set it at 5800. A couple of major factors should be considered. Prop pitch and longevity of a Alpha SS drive. Sure, I intend to visit 5800 which will be infrequent and swing no larger than a 25p Hydro OT. I hoped for a strong power plant which I think I have and will be happy with a limit of 70. It is also nice to say " I almost have a 500/500".
    The build. Block, O decked, SRP 16cc dished pistons for a comp. ratio of 9.7 and 6" rods. AFR 195 Elim. alum. heads, Edel. Rpm airgap intake and a 750 holley. Prem. fuel only. Stuffed in a 18 Classic.
    AFR heads are pure art work.

  7. #7
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    excellent choice of parts
    Charter Member - WAFNC, SBBR, KWOSG
    1955 Perfect Mate
    1986 Hornet III, 502-415 TRS

    www.donzi.org


  8. #8
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    How's your quench?
    Cheers,
    Pismo
    1996 22 Classic
    Red with Stainless Windshield
    Stock Gen VI 502 Magnum MPI-415hp
    Stock Bravo I
    25" Mirage Plus
    74.5mph best @ 5050rpm GPS (Speedo said 80)
    27" Labbed Mirage Plus
    75.5mph best @ 4800rpm GPS (Speedo said 82)

  9. #9
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    Nice motor.
    Thinking of the same engine for my 16

  10. #10
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    Quote Originally Posted by Pismo View Post
    How's your quench?
    Tight, .038 Felpro gasket.

    Want to thank Mr. Fix for his help and advise.

  11. #11
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    Quote Originally Posted by BUIZILLA View Post
    excellent choice of parts
    Thanks Buiz. Getting a compliment from you Fl. boys is tough.

  12. #12
    mrfixxall Guest

    Fixx

    Quote Originally Posted by tmdog View Post
    Tight, .038 Felpro gasket.

    Want to thank Mr. Fix for his help and advise.

    Any time jim!! Now let's hope it warm's up real QUICK so you can get a video of that little monster in action for us..

  13. #13
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    Cant wait to see how this and an ss runs in a 18 instead of a 16
    Well done
    Parnell
    Time forSweet Cheekz to find a new home

  14. #14
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    Congrats!

    Congrats, nice work! I'm in the process of building a similar motor but I have a constraint, I can only get 87 octane. Out of curiosity, what octane gas are you running in the boat? Again, nice work!
    DUNESMAN

  15. #15
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    Nice numbers. Congrads!
    2001 35 Fountain Lightning w500 EFI's
    1973 X-18 - Merc 383 Magnum
    1974 Chris Craft Roamer with 1271 TI's

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