BBC blower engine

Discussion in 'PSI Superchargers Tech Questions' started by vht, Sep 14, 2011.

  1. vht

    vht Member

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    New to this site, so if I make any mistakes let me know. I have a Spitzer, 235 in 4 link dragster with a 582 on alky. Car runs low 4.60's. I'm wanting to build a blower motor using a 871 with injection to run some quick 8's and also bracket race it. I'm open to suggestions on eng size and comp ratio. What about tall or short deck blocks? My eng now has over 15 to 1 comp with Ron's inj. I figured I'd be better off selling it and starting fresh with less cubic inches. Instead of trial and error I figured I'd talk with some of you that maybe have run something close to what I'm looking for. Any help will be appreciated, thanks.
     
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  2. WANNABE

    WANNABE New Member

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    Got no problem with the cubic inches. As long as the block is strong, it should be fine.
    The valvetrain does not know your cubic inches. We had lots of guys running high 500-6teen cubic inches in their blown BBCs. They just spun no rpms with a taller gear and larger tire and the engines lasted a long time. It is when you are trying to run all out that the long throw and big inch deal starts to kill you.
    But I say - if you have the crank, block, rods, etc. . .
    As for compression, a higher compression engine will idle a little better, and tend to be a little more consistant with drastic air changes. About 12:1 is about right. And then you don't need a really efficient blower.
    Tall decks work as well as short. Just whatever you have and find a manifold for.
     
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  3. Moparious Maximus

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    I run a 572 mopar 4.500 x 4.500, did the same thing you are talking about. It was originally a injected alky NA motor 14.7 to 1, now its 11.6 to 1 with a std helix 8-71 and im really impressed with the thing. Its in a 3250 lb door car, turn it to 8k and its best time is a 7.99.

    I might consider shortening the stroke some, might help the launch some, those long arms make BIG low end torque.
     
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  4. vht

    vht Member

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    Whichever way I go I'll use a dart block. I know of a new one, tall deck, that I can get for $2000. I figured a stock stroke would put me at around 532 cu. in. I've been told the bigger the eng the bigger the blower you have to have otherwise you'll have to work a smaller one harder. A friend of mine has a 496 bbc, with a 871 that has been 4.37 in the 1/8. Will a 7al2 with a msd long duration coil and crank trigger do the job? Thanks for the help.
     
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  5. jim phillips

    jim phillips ta/fc

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    it doesnt nessisally take big cu.in. to go low 4.s i have done it with 514bbc and a 1071 47 over 12-1/2to1 dart alum 360 heads alum rods

    540cu.in with a 1471 with good parts will do the trick easily in a dragster 4.0s are teens for sure
     
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  6. alt 6153

    alt 6153 Member

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    I run a 540 and shift at 7500-7700 and run 4.30's 1/8th and 6.85 ish 1/4 mile at 3000ft air. 2200 lbs altered. 10:1 compression. (easy to tune and easy on parts). The lower compression is more forgiving on the tune up. High compression will make more power.........if your tune up is right!! if not......Well you know the story. As far as the 7al box...... It will work to about 18-20 lbs of boost....after that the fire goes out... I run a 8 plus with the HVC ll coil. Still lit at 28lbs of boost. so far so good....
     
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    Last edited: Sep 16, 2011

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