Stock rods&cranks How Much can they take

Discussion in 'High Performance Modifications' started by f-body, Jun 20, 2009.

  1. Louich

    Louich Veteran Member

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    we ran our 355 for 1 year drag racing shifting at 7500 and then changed heads and cam went 3 years in the roundy round turning 7600, stock crank, stock rods with arp bolts. now in a 86 camaro with aluminum heads on the street and never touched the bottom end. one of those shoulda kept it engines :)
     
  2. quick80Z-28

    quick80Z-28 Veteran Member

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    355 4 bolt. G.M. steel crank and g.m. x rods with arp bolts. Shift at 7 grand on healthy shot of nitrous. Just don't detonate it. Been alive for 3 years with lots of street miles.
     
  3. yobin67

    yobin67 Veteran Member

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    My 355 came out of a 1970 1 ton truck.2482 main caps,X-rods,factory steel crank,flat top TRW forged pistons.I built it in 1989.It's been hurt once and freshened once,and is still in the car.As a 4 speed car it saw 8000+ a lot before I got a rev limiter.It now sees 7000-7500 all the time,and still runs well.
     
  4. jester1

    jester1 Veteran Member

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    Thats the million dollar question.
    The boosted crowd on a regular basis. Ive seen a couple crack and most usually bend. THe broken cranks all had fubared pistons. Total tune way off the deep end.
     
  5. Simon@London

    [email protected] Veteran Member

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    A lot of this speculation on stock components is based on oval cars running 7,000 down back stretches and I have watched them a lot. But they don't sit there for long but one common issue never gets mentioned on rev's of stock parts. COOLING.......you keep them cool and they'll likely run until the cows come home but get them hot......:whine: it's over real quick. Usually the smog heads pooch out before the cranks or rods.
     
  6. anesthes

    anesthes Veteran Member Lifetime Gold Member

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    I think a lot of you guys are not keying in on the application.

    An ovaltrack car maintaining speed at 7500 RPM, vs a heavy 2nd gen (3600lbs), launching with slicks on a manual transmission at the drag strip.

    I sometimes ponder the question, is a forged crank worth the extra money.. On my last build (358) I used a forged crank, 5.850" h beam rods, etc. It never saw more than 6400 rpm.

    On my current 412 build, I'm half tempted to use a stock 400 crank, but again I wonder if a good launch at the track will break the crank.

    -- Joe
     
  7. 80'427

    80'427 Veteran Member

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    I have seen broken cranks in stock tahoes and trucks. Anything can and will break. I perfer bullet proof but I have built lot of stock bottom end engines that have seen lots of passes and rpms.
     
  8. BIGBADBOWTIE

    BIGBADBOWTIE Veteran Member

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    The last engine that was in my Z was a flatop,aluminum headed, solid roller 355. It had a cast GM crank cut 10/10, polished GM rods and KB pistons. It had ARP hardware and was well balanced. It was together for over 5 years. It ran consistant 10.7x @125-127 in the qtr. That was shifting at 7k and shooting 125 to it. The the short block minus cam has been freshend and is now in my 86 c10.

    edit.... Would I do it again. N_O. it was a time bomb just wating to scatter.
     
    Last edited: Jun 26, 2009

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