How much can sbc 400 stock rods and crank handle?

Discussion in 'Engine Topic' started by z28rod, Dec 9, 2010.

  1. z28rod

    z28rod Veteran Member

    Apr 30, 2009
    hopewell junction,ny
    My best friend is building a stock bottom end sbc 400, bored .30 over to 406, stock gm crank cut 10/10 , 5.565" stock rods shot penned and resized with arp rod bolts, the rotating assembly will be balanced with speed pro hyper. flat top 4 eye brow pistons. we are discussing the max hp this stockish bottom end could handle on 93 oct. gas no nos. he says 450 hp , i say 500 plus some as long as its street ran 90% and raced 10% of its life and not reved over 6500rpm..... he plans on using alum heads with 70-76 cc chambers, wants about 10.5-1 comp. and a flat tappet cam of under .500 lift..... oh headers 1 5/8" duals and hei with 750 holley d/p, 4 peed with 3.73 eaton posi 10 bolt. He has a 80 malibu wagon, he is running my 350 out of my z28 right now, its a flat top rebuild with mild cam and home ported heads, maybe 300 hp... but now he loves my 406 so he wants one for his wagon. I am trying to talk him into getting at least a nodular stl. crank from scat. Any ideas to help us end our arguement.
    Last edited: Dec 9, 2010
  2. frankz

    frankz Veteran Member

    Aug 24, 2009
    The best way to end that argument is to agree on 475HP!!! j/k
  3. z28rod

    z28rod Veteran Member

    Apr 30, 2009
    hopewell junction,ny
    Ha to funny, but was looking for a more technical explanation haaaa was funny though.
  4. MyBoTy

    MyBoTy Veteran Member

    Feb 9, 2002
    Lubbock, Texas USA
    Stock rods are his weak points, he'd do a lot better with some 5.7's. GM had to remove some beef for clearance, it came right off of the shoulder of the rod.
    That crank is nodular, they'll generally outlast the block, 500hp is fairly common out of 'em.
  5. 79RedZ

    79RedZ Veteran Member

    Mar 24, 2009
    I would think the rpm that he is planning on spinning it too would be a bigger factor. Keep it under 6000 would probably be best for the stock crank and rods, actually 5500 would be a better number. If he is going to turn it over 6000 I don't think I would trust that. just my 2 cents worth.
  6. high impact

    high impact Veteran Member

    Sep 14, 2010
    NW Indiana
    The crank isn't the short coming - the rods are. Put some aftermarket rods in that bugger and let her rip.

    I ran a 13.5 to 1 compression solid roller cam 406 with a gm cast steel crank, aftermarket rods (eagle, oops), forged pistons producing close to 600 hp for many seasons and it was fine. It had a 4500 9 inch converter, transbrake and 10 inch slicks, I ran it on the street and strip - this thing screamed to 6500 rpm too many times to count. I was really happy with this engine other than its deep thirst for race fuel.
  7. middleagecrisis

    middleagecrisis Veteran Member

    Oct 22, 2007
    SA, TX
    More than a few years ago I ran a completely stock bottom ended 400 SBC that began life with me at the 90K mark. I slapped some double hump heads on it, a TM-1 intake and a Comp Cam 280 Magnum cam. That motor was a daily driver and saw 6K RPM shift points on a regular basis. I ran that motor for another 30K miles. I rebuilt it and added TRW forged pistons, ARP rod-bolts (stock rods), balanced it, added a .550 lift solid cam and improved the oil system. I ran that motor to 6500 RPM and higher on a few occasions. The next owner of my Camaro suppodesly blew up the motor I never could. If you keep below 6000 RPM and keep the motor naturally aspirated (no nitrous), my personal experience is you'll be fine. My .02 worth.
  8. 6KMile70Z28

    6KMile70Z28 Guest

    I always recommend using 5.7" rods. The 400 rods will be the weakest link in your engine. You must check camshaft lobe to rod clearance when you do this on cylinders 1,2,5 and 6. I have failed the 400 rods in a 450 HP engine.
    I believe that the throttle response, or acceleration rate is the key factor, not the peak HP. If you use stock heads, maybe not an issue.
  9. NYH1

    NYH1 Veteran Member

    Feb 27, 2010
    Central New Yorkistan
    HERE are some Scat forged 5.7" stroker "I" beam rods with cap screw bolts. Not to expensive, and good insurance.
  10. wild84

    wild84 Veteran Member

    Jun 2, 2009
    Las Vegas, nv
    Um..... mabey I'm skeptical, but I dont see 450 hp, let alone 500 out of a hydrolic flat tappit with less than .500, and only 1 5/8 headers. Better be some really good flowing heads. Anyways, good luck.

Share This Page