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Stock 4.6 2 valve shortblock RPM capability

Discussion in 'SN-95 and New Edge Mustangs' started by budman5023, Jul 30, 2019.

  1. budman5023

    budman5023 Member Established Member

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    Colorado
    I have been searching for a while now and haven't found anything. Given the right cylinder heads, valvetrain, and maybe even upgraded oil pump, what can I safely spin the cast crank, cast rods, and hypereutectic pistons too. I would assume a rod would go first, but doesn't the 5spd cobra and mach 1 spin 7k on that same rod. I was told by one big mod motor building company 6.2k. But idk. Any thoughts? My head has been going crazy with motor builds for the race car.
     
  2. 2000GTSTANG

    2000GTSTANG Well-Known Member Established Member

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    If you're NA, keep it under 7k and you'll be fine.
     
  3. Jwilso53

    Jwilso53 New Member Established Member

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    Aug 18, 2018
    Location:
    Georgia
    The nodular cranks flex more than forged and rpm is what kills them. I’d rather run more power with boost at a lower rpm than spin a cast crank to 7k.

    Just made 460/465 this weekend with stock intake, valvetrain and heads.
     
  4. StrayBullitt

    StrayBullitt Well-Known Member Established Member

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    Seattle (GO HAWKS!)
    I'd say 6500 if you want to keep it together, what are your build thoughts to make power past this point ?

    My last 2v with stage 3 cams, trick flow heads and Eddy intake started to nose over at 6400, there wasn't much reason to rev too far past 6500.

    I've never seen Cobra/Mach rods in person next to 2v rods, but I believe there is a little bit more meat on the bones of the 4v rods.
     
  5. blownstang4.6

    blownstang4.6 Active Member Established Member

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    Nov 8, 2011
    Location:
    Chicago
    6500. My Mach makes 508rwhp through an auto on the stock motor. Have it shifting at 6k on the street and 6.5-6.6k at the track. 4v and 2v cast crank and rods are the same. The cast crank is perfectly fine if keeping rpm under 7000 and power under 700rwhp.
     

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