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Thread: 421 build up for a boss hoss

  1. #1
    Senior Member MASTER BUILDER
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    421 build up for a boss hoss

    ok guys, lets have it, we are building a customer a SB 421 stroker with AFR heads, goal is 600 +hp with 10.5:1 compression, will be using AFR 210 heads. And an air gap intake, as this is all the more room we have for height.

    What roller cam ? I have mine picked out, but want to see how good the forum is!
    Oh, we will dyno the engine so I will post the results.
    Competition Engines & Hardcore Engine Parts
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  2. #2
    Senior Member MASTER BUILDER
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    600hp should be easy. I recently did a 406 that made 646hp and 557 ft/lbs on pump gas, with Platinumn 230's. I am not talking cam specs though. lol

    Frank
    Advanced Performance
    www.get-ap.com

  3. #3
    Senior Member RACING JUNKIE
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    I agree with Frank,
    600hp is pretty easy. This cam, made over 600hp with brodix track 1's and an 850 holly with 406". although i did a little damage to the cam when i broke a rod bolt, i had bullit regrind it back to the same specs. it went 6.50's @ 3200lbs. with 12 to 1's.

    JMO

    Zip.


  4. #4
    Senior Member RACING JUNKIE jmarksdragster's Avatar
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    Look for a cam with actual lift (minus lash plus rocker ratio to get actual) to put you .080 to .100 to coil bind (with good springs). 270 to 275 @.050 intake and around 8 to 12 more on exhaust. 106 LSA unless NOS will be involved, then go 112. A 421 should go 600+ HP easy enough.
    Mark Whitener
    http://racingfuelsystems.myfunforum.org
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    Good work isn't cheap, and cheap work can't be good.

  5. #5
    Senior Member MASTER BUILDER
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    We have built a few engines for boss hoss's, and, they are insane. We have one guy, that we are building a 598 tall deck BBC for one. These are true street cruisers, and, solid roller cams aren't the best choice for them. Besides, The stock 355hp 350's or 502hp 502's will light the tires for as long as you want. One local guy has a 632 engine in one, that makes 830 ish on the motor, and 1100 on the bottle, lol. Thats plain rediculous, but, he is the local dealer for them, and, his bike has got to be outragous.

    If you ever imagined riding a a V-8 engine, by itself, thats about as close to it as you can get. They are described as being the biggest speed thrill there possibly is. As totaly over kill as they are, they are still cool

    Frank
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  6. #6
    Senior Member MASTER BUILDER
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    we have a couple Boss Hosses around here that go to local car/bike shows, theres one that is a BBC, not sure of cubes but when he revvs in neutral he damn near tips it over because of the torque :shock:

    I cant imagine having 600+hp in a 1500 or less lb STREET vehicle, thats insanely fast. :twisted:
    1987 Pontiac Fiero GT
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  7. #7
    Senior Member MASTER BUILDER
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    Typicaly, the radical engines we do for them, use all aluminumn engines, to keep weight down. So, in reality, your talking around 1200 pounds, with the rider, tops. Most are around 1000lbs, with the all aluminumn engines. Like I said, I have personaly wrode one, and really don;t care to, but, the guys we know with them, describe it as the biggest speed rush there is.

    Frank
    Advanced Performance
    www.get-ap.com

  8. #8
    Senior Member EXPERT BUILDER
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    Re: 421 build up for a boss hoss

    Quote Originally Posted by cncmotorsports
    ok guys, lets have it, we are building a customer a SB 421 stroker with AFR heads, goal is 600 +hp with 10.5:1 compression, will be using AFR 210 heads. And an air gap intake, as this is all the more room we have for height.

    What roller cam ? I have mine picked out, but want to see how good the forum is!
    Oh, we will dyno the engine so I will post the results.
    How is the build-up going? Get it on the dyno yet? 8)

  9. #9
    Senior Member MASTER BUILDER
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    We are 3 weeks out yet, we have about 10 engines to finish up first.
    Competition Engines & Hardcore Engine Parts
    www.cnc-motorsports.com
    [email protected]


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