Engine size change & Overdrive

Discussion in 'PSI Superchargers Tech Questions' started by Blownalky, Jun 30, 2008.

  1. Blownalky

    Blownalky Top Sportsman

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    Changing engine size from a 468 to a 548 BBC, had a little boo-boo with the smaller engine. Those diapers are certainly worth their weight in gold. To get me back on the track in time for the next race, I'm going to put the same intake, injector and blower back on. The blower is a Littlefied 8-71, std helix that made 26lbs at 32.9% over. Currently have a Bird with just hat lines, 58 nozzles, 135 main and a 65 in the high speed. Besides having better flowing heads, the engines are essentially the same except for size. Was looking to see what I'd need to spin this to get me back in the ballpark on this bigger engine. Oh yeah, would eventually like to go faster too. :D

    I have a 14-71 SSI, bigger injector and a better intake but I can't get this on and fitted properly to make the next race.
     
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  2. SoDak

    SoDak Active Member

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    Your going from what heads to what heads?
     
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  3. Blownalky

    Blownalky Top Sportsman

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    From a set of Bob Morgan prepped 861 Bowties that flowed about 375 @ .700 (don't have an .800 number) to a set of AFR 357 which flow 415 @ .700 and 425 @ .800.
     
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  4. TAFC 5 81

    TAFC 5 81 Member

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    I would say the 80 cu. in. will add some power and torque. I would think you will need to add some fuel to feed that beast. How heavy is the car?
     
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  5. SoDak

    SoDak Active Member

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    I have run setups extremely similiar to this.
    The bigger engine and the better heads will make the boost number drop but the HP will go up. More air will get into the cylinders therefore you need to add fuel.
    If it were mine I would richen the main by .015" (15 is a guess), leave the pulleys alone and go.:)
     
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  6. Blownalky

    Blownalky Top Sportsman

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    It's about 2700 LBS.



    SoDak, thanks for the info, will give it a shot with that set up. Was kind of leaning that way. I have several other pulley combinations but I can always try them later.
     
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  7. MKR-588

    MKR-588 Member

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    Are you sure the AFR 357 flow as advertised as mine didn't
     
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  8. Blownalky

    Blownalky Top Sportsman

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    Haven't had these flowed, what did your's come up with?
     
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