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Another "how does this motor setup sound" question.

Discussion in 'The Garage' started by y5mgisi, Aug 12, 2004.

  1. y5mgisi

    y5mgisi 1 ton status

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    Another \"how does this motor setup sound\" question.

    I know this question gets asked alot but the search dosnt help out a whole lot. So here goes.

    Rebuilt 350 short block.
    vortec heads(or some other like pro toplineS)
    edelbrock performer manifold.
    268H comp cams cam shaft
    Rebuilt Q-jet
    1-5/8 long tube headers and true dual 2" exaust w/ flowmaster 40s
    accel plug wires and coil
    and autolite 26's

    So what do you think? Think it will make better than 300hp and more than 350 lb/ft of torque? oh and also it has pretty good heads on it. I think they were ported at one time or another when my dad had it. And it has high performance valve springs on it for sure cause i can tak the motor to 6500 rpm no problem. so tell me what ya think. /forums/images/graemlins/thumb.gif
     
  2. 1-ton

    1-ton 1/2 ton status Premium Member

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    Re: Another \"how does this motor setup sound\" question.

    In order to get 300 HP out of a 350, you are going to need flat-top 10:1 compression pistons at least. If you want 300 HP from a small block, with lower compression 9:1 to 9.5:1 pistons, then you should consider a stroked 377 or 383 small block. This will get you the 300 HP you are looking for.

    All of the bolt on stuff you are talking about (manifolds, camshafts, headers, etc) is only good for about a 20 to 25 HP increase.
     
  3. POWERMAD

    POWERMAD 1/2 ton status

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    Re: Another \"how does this motor setup sound\" question.

    This may shed some light.
    I was diggin through an old Petersons camshaft and valvetrain rag and seen this write up on different cams.
    9.7:1 355
    AFR heads, 2.02/160: 190 runners.
    Ebrock Performer RPM intake

    Holly 750 dbl pumper
    Comp 268H cam
    Hooker 1 3/4" headers
    380hp @ 5,400/401 torque @ 4,100
    It made at least 400 ftlbs between 3700 - 4300 and over 350 ftlbs between 2700 - 5600.
    Over 350 horse from 4700 - 5800.
    It idled at 800 rpm with a slight lope and 16 inches of vacuum.
    Good write up. they did Comps 252,268,280 and 292 grinds with the same plant to see what each one would do.
    The 268H cam was the best choice from that line up with that particular plant.
    It idled the best and had the flattest tourqe curve.
    The article stated that the 252 would have had better numbers had a performer intake, smaller carb and headers had been used.
    The 280 seemed to be matched but it had a choppy idle and a 2500 stall converter would be needed.
    The 292 would have done better with a single plane intake like the Victor JR and at least a 3000 stall converter would be needed.
    Everything was used out of box and all dyno runs were on 92 octane.
    They used a Comp timing belt and had tall Comp covers on it so I would assume it also had Comp roller rockers.
     
  4. 1-ton

    1-ton 1/2 ton status Premium Member

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    Re: Another \"how does this motor setup sound\" question.

    [ QUOTE ]
    9.7:1 355
    AFR heads, 2.02/160: 190 runners.
    Ebrock Performer RPM intake
    Holly 750 dbl pumper
    Comp 268H cam
    Hooker 1 3/4" headers
    380hp @ 5,400/401 torque @ 4,100


    [/ QUOTE ]

    380 HP? This is a lot of horsepower out of a 10:1 flat top .30 over 350 engine with an RV cam, and some bolt on parts. Frankly, I find it hard to believe.

    I put together a .60 over 350 engine with aluminum 2.02 and 1.60 (64cc) heads, 310 degree mechanical lift camshaft, 12:1 compression pistons, Wieand intake, Hilborn mechanical fuel injection, and zoomy style dragster headers. It was run on methanol, and sat in between the frame rails of a 160 Ft. wheelbase Super Comp Dragster. This engine was dyno'ed at a little over 390 HP.

    How could an engine with flat-top pistons, and an RV cam put out almost the same Horsepower? Getting 1 HP per cubic inch takes a lot of modification, and getting more than 1 HP per cubic inch turns the motor in to a potential hand grenade.
     
  5. POWERMAD

    POWERMAD 1/2 ton status

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    Re: Another \"how does this motor setup sound\" question.

    What is so hard to believe?
    What would they have to gain from testing all those cams and lie about the results? Comp paid em off to write up bogus results??? I seriosly doubt that.
    The purpose of the article was not to sell cams but to show what happens when an engine is over cammed.
    IIRC Ebrocks RPM package dynoed 420HP with a 355. But they prolly pumped those figures up just to sell their stuff. /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif
     
  6. k5james

    k5james 1/2 ton status

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    Re: Another \"how does this motor setup sound\" question.

    IMHO it's all in the heads. Those AFR heads are some pretty high flowing heads out of the box. What kind of aluminum heads were you running on that dragster?
     
  7. 1-ton

    1-ton 1/2 ton status Premium Member

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    Re: Another \"how does this motor setup sound\" question.

    [ QUOTE ]
    What kind of aluminum heads were you running on that dragster?


    [/ QUOTE ]

    Brodix Cylinder heads.
     
  8. 1-ton

    1-ton 1/2 ton status Premium Member

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    Re: Another \"how does this motor setup sound\" question.

    [ QUOTE ]
    What is so hard to believe?

    [/ QUOTE ]

    Well, I guess it must be possible because the GM Performance ZZ/350 crate engine is rated at 350 HP, and it has similar specs as the one in the article you posted. Sometimes I wonder about the truth of these HP ratings?
     
  9. y5mgisi

    y5mgisi 1 ton status

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    Re: Another \"how does this motor setup sound\" question.

    HMMmm... Some good info. Sounds like i might get to see 300 hp from this combo. Oh yea forgot about the pistons. Id like to stay 9:1 or below becasue its going to mostly be parked out in the boonies at our cabin, And all they got for gas out there is /forums/images/graemlins/rolleyes.gif So can i get flat top pistons that will get me that compresion ratio with the vortecs? And to 1-ton I seriously appreciate your comments but it is way way common to see a 350 put out 300 street happy horse. And not hard to build a 400 horse 383 that also wouldent be bad on the street. So i dont know why yours only made 390 hp(as if that wasnt very much) /forums/images/graemlins/thinking.gif
     
  10. POWERMAD

    POWERMAD 1/2 ton status

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    Re: Another \"how does this motor setup sound\" question.

    [ QUOTE ]
    Id like to stay 9:1 or below becasue its going to mostly be parked out in the boonies at our cabin, And all they got for gas out there is So can i get flat top pistons that will get me that compresion ratio with the vortecs

    [/ QUOTE ]
    I believe that will be 10 and above.
    I just got done researching this all out. Heads with 76cc or so chambers and flat tops will get ya around 9.
    That's a guestament. To know for certain you would have to have all parts and measure everything.
    As to the HP debate the same dyno run with the cams.
    with them running the 292H it put out 399 ft lbs (lower than the 268 and 280) but put out 430 hp at 6700 rpm.
    They said a single plane intake like the Victor Jr would have added another 20 hp.
    That wouldn't be very streetable though, although a light car with a 3,000 stall converter would be pretty quick.
    I wonder what those guys get to do with those plants that they flog on the dyno.
     
  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Another \"how does this motor setup sound\" question.

    Smaller cam, 268 is too much for a 4x4
    Bigger intake (Performer RPM)
    Bigger exhaust pipe
    I'd go with better heads than vortecs
     
  12. hi pinion

    hi pinion 3/4 ton status

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  13. crazyrc

    crazyrc 1/2 ton status

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    Re: Another \"how does this motor setup sound\" question.

    If you're looking for the best possible cam go with a comp cams 4x4 roller cam. It will cost you more, but you get the best of both worlds.(Less sacrificing H.P.for torque.) /forums/images/graemlins/peace.gif
     

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