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Which Heads?

Discussion in 'V8 Development and Modification' started by Lexx, Jul 22, 2006.

  1. Lexx

    Lexx New Member

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    I am going to rebuild my VR V8 later this year and have been told I should get some VN V8 heads as they flow better.
    Is there a factory fitted head that is better than the others for the injected V8's?
     
  2. RVN 355

    RVN 355 New Member

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    Not that i know of, Just get ur's ported and polished,simple valve /seat. VN Heads do flow better but @ the end of the day whats ur kw Goal ? There is alot more to do b4 ur heads with greater bang for bucks just a suggestion -

    Benchmark 220kw + @ Engine

    Exhaust - Twin Magna flow Cats,Stainless System,Lukey Ultra Flow,2.5 - 3"

    Camshaft - 214 - 188 Hydryalic Duration Cam@ 50 tho which = good midrange + good bottom end torque.

    Inlet Manifold Stock Inlet is restrictive have a look into the Active Manifold Root/ Four Barrel Conversion- VL / VN Group A twin throttle body setup or go the come racing option

    3000High Stall Convertor, Shift Kit, 3.7.3 rebuild LSD,

    Standard Valves are good for 300kw
     
  3. Lexx

    Lexx New Member

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    At this stage I'm not really going for a set power figure. However, I'll never knock back more horse power!! :yeah:
    The bottom end will be rebuilt and balanced, compression in the range of 9.5 to 10:1, yet to determine the cam, roller rockers, intake will be what ever I can afford at the time (hopefully VN GpA), twin cat exhaust all the way, diff will be 3.7 lsd, auto to be rebuilt and kitted. I'm not a big fan of stall converters, so I'd like to keep the converter as close to standard rpm as I can. :thumbsup:
     
  4. AirStrike

    AirStrike Administrator Staff Member

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    Choose your cam first, everything revolves around that.
    AirStrike :air:
     
  5. greenfoam

    greenfoam New Member

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    I'd say choose your compression first then choose a cam, a big cam is pretty useless with low compression, have a serious think about a stroker motor. For the price you will have to pay to get a group A manifold (over 3 grand at least) you would be well in front with the stroker and doing the 1/4 mile faster. This also goes to plan with your stock stall converter.

    Say 355 stroker, 9.5:1 compression, anywhere from stock to Crane 276 cam decent springs, forget the rockers, stock manifold, high flowing dual cat, dual 2.25 inch exhaust some 775 injectors, a good strong tune and you'll be ripping holes in the road. VN heads don't flow any better than VR it's just that the VN heads are supposed to be a slightly thicker (I think) casting but for a low rpm motor you wont need to or hardly need to touch the heads anyway so that's not worth even thinking about
     
  6. RVN 355

    RVN 355 New Member

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    I agree www.tuffcarparts.com.au sell a 355 stroker kit for a good price, something to think about and Engine Managment, If you want bigger numbers go the 284 Crane Cam but internal mods,zorst,strong trans and cooling system is must.
     
  7. geardys

    geardys GEARDY

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    A simple port would be enough for ur job. i wouldn't go for a polish because it will disturbed the air flow to much with a low rpm engine. also try and get some hsv valves because they are shaped different and allow for a little extra flow, without touching the heads. but don't for get a decent set of extractors and i'd go twin hi-flow cats into a twin 21/2 in.


    the stock manifold is really good at making low down power and torque , even better then the Group A set up and Active Manifold. but once above 3500-4000 its no good at producing peak figures and its plane useless over 5000rpm.

    so if its a weekender or u won't heaps of top end power with little loss in the lower rpm range try the star manifold. its exactly the same as the old manifold but has been ported to flow better, 1200cfm. so its going to be easier to put in then an active or groupA. they are around $1450 exchange

    http://starrperformance.com.au/inde...5348453-5767&parentContent=1119935321390-1333

    as for the compression ration 9.50-10.0 is a good figure. u'll be able to run a good cam or later on down the track a blower.

    also as greenfoam said "think about a stroker motor". for the price u save on the manifold u'll be able to afford one. If its a late model vr or vs block u might be lucky and the block will allready be cast so that it can fit the stroker rods. thus saving u money. a good stroker like greenfoam explained should make around 230kw's@fw & 500nm with stock manifold and 250+ kw with an after market one..
     
  8. Lexx

    Lexx New Member

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    Thanks for all the advice people, but I'm still thinking only 5.0l. I would really like to get my hands on a 1970 Dodge with a 440 or 426 in the next couple of years so I don't want to waste too much on building a Commo only to end up selling it cheap to fund a Dodge (but I'd rather keep the Commo and still buy a Dodge!! :yeah: ).
    With this in mind, if I build a stroker and sell the car, the stroker goes with it. If I build a fresh 5.0 and bolt on a twin throttle and/or blower, I can remove them if the car is sold and get some sort of a return on those parts.
    Not only that, I'm doing as much of the spanner work on this motor as I can. If I went stroker then I'd end up with Chev rods, forged pistons, big ass roller cam ect ( I know myself too well ). Then I'd end up paying some one else to build it. I want to have a go at doing this engine myself ( with direction from an engine builder friend of mine ).
    So it's looking more and more like a good tuff 5.0l with bolt ons for now.

    It's shaping up something like this..........
    Full tear down and rebuild
    9.5 to 10.0 to 1 Compression
    Possible replacement of valves (thanks geardys)
    Port match on the heads - done by Myself Engineering in Sydney
    Balance the bottom end
    As big a cam as the standard auto stall will allow
    Twin cat exhaust all the way through (already got Pacemakers fitted)
    Memcal re-map
    3.73:1 LSD

    :driving:
     
  9. V8VLCALAIS

    V8VLCALAIS Guest

    gday mate ive just built a 355 stroker carb setup its running dimond flat top forged pistons scatt h beam rods harrop highrise manifold a 280 crane cam harrop crank and i brought abha-9 yella terra aliminuim heads there the best heads u can run on a 308 ive had mine ported and polished the heads cost nearly $4000 but are awsome hope this will help ur decision
     
  10. RVN 355

    RVN 355 New Member

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    sounds tuff,what numbers u getting out of the 355?
     
  11. immortality

    immortality Administrator Staff Member

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    get the heads ported and flow tested, give these figures to your cam supplier along with the rest of your engine combo + what your aiming for and they will custom grind a cam for you, give you the best compression ratio to use with your new cam etc a custom grind should perform better than anything of the shelf as long as your honest with the info you give the cam grinder and you have realistic goals, sticking to the stock converter is deffinitly going to limit things though but the cam manufacturer should be able to give you the minimum stall required for the cam you end up with.
     
  12. RVK 355

    RVK 355 M0DERAT0R

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    VN-VS heads are the same, its only the VT heads (or roller motor) heads that have a different style chamber, less CC and a love heart shaped chamber
     
  13. Lexx

    Lexx New Member

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    $4000 heads and a stroker!! You would've been better off doing a GenIII conversion. They're already fitted with alloy heads! lol
     
  14. RVK 355

    RVK 355 M0DERAT0R

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    couldnt to a complet gen3 conversion for 4k though, thats the price people pay when chasing HP
     

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