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400 sbc build??

Discussion in 'The Hokey Ass Message Board' started by Dan, Oct 10, 2012.

  1. Dan
    Joined: Mar 13, 2001
    Posts: 2,384

    Dan
    Member

    Looking for info on different 400 sbc combos - I have one that I would like to start playing around with...
    will need to use stock heads (budget)
    does need a crank so am open to options there...
    does need two rods so am open to options there as well...
    put it all back together with 400 rotating assembly?
    see that a 377 is possible with mostly "off the shelf" stock parts, is that desirable?
    What to do?
    This will be a street driven, auto trans, but I am a sucker for a lopey idle (have been guilty of overcamming projects in the past :) )

    If this has been discussed, I have yet to find a thread, if so would appreciate links or any other info-
    thanks!
     
  2. BOBCRMAN
    Joined: Nov 10, 2005
    Posts: 846

    BOBCRMAN
    Member
    from Holly

    Depends on your budget.

    A fairly inexpensive way to go is this.
    A flat top piston with a 5.7" (350) rod. 400 crank. 76cc. (stock) heads.

    Don't bore block over .040" (.020-.030" is best). Block must be plate honed to make horsepower. 400 blocks/cylinders move around a lot.

    350 rods will have to be ground at the head of the rod bolt. To clear camshaft. Lumpy cam on a budget is a [email protected] by .488 lift. Can use a stock converter on most apps and will idle and power brakes work. Been around since back in the day and inexpensive. Inexpensive Z28 style springs.

    Have built/used and sold many of them.
     
  3. Really!?!?

    It's a little difficult for a "siamese cylinder" block to "move around". That's why it's well liked in drag and roundy-round racing.

    They are however notorious for core shift.
     
  4. Biscayner
    Joined: Jul 1, 2009
    Posts: 54

    Biscayner
    Member
    from MN

    If you want a 400 that screams then by all means find a used set of vortec heads. Drill them for steam holes then add some better valve springs, a vortec intake and your favorite cam and that puppy will be a great engine. My buddy did that to his as per my instructions and he says it pulls like a 454.
     

  5. Yea that certainly will work but the O.P. stated that he's on a budget. Heads are out!

    However, I'm pullin' 5xx+ horse with just iron Sportsman heads on my 408.
     
  6. GOATROPER02
    Joined: Mar 22, 2006
    Posts: 2,059

    GOATROPER02
    Member
    from OHIO



    Dont kid yourself.....Even a 350 block will distort when the heads are torqued on....thats why we use block plates.....On a 400 the cylinder is even closer to the bolt holes and block plates are a must for good ring seal.

    And yes Ive built many of them for drag and circle track long before aftermarket blocks where common place.

    Tony
     
    Last edited: Oct 10, 2012
  7. Tony,

    Torque plates and movement are obvious with any engine. Hell I use torque plates when I do Harley cylinders. The comment was that the 400 moves around a lot. Moving around "a lot" is not the case and certainly not more on a 400 block.
     
  8. GOATROPER02
    Joined: Mar 22, 2006
    Posts: 2,059

    GOATROPER02
    Member
    from OHIO

    Really?
    I guess .0025-.003 and hexagon cylinders aren't alot some people......Around here we use the 4th decimal .0000 place and prefer it that way.

    I'm sure thats what the man meant by "moving around"

    Tony
     
  9. slammed
    Joined: Jun 10, 2004
    Posts: 8,150

    slammed
    Member

  10. BOBCRMAN
    Joined: Nov 10, 2005
    Posts: 846

    BOBCRMAN
    Member
    from Holly

    Exactly.. 400's are also known for deck cracking, around steam holes, into head bolt holes and cylinder bore. Terrible deck tolerance also.
     
  11. BadgeZ28
    Joined: Oct 28, 2009
    Posts: 1,165

    BadgeZ28
    Member
    from Oregon

    I added hardblock to my modified 400. Filled up to just below the soft plugs. A high performance 400 requires a good cooling system.
     
  12. Dan
    Joined: Mar 13, 2001
    Posts: 2,384

    Dan
    Member

    A flat top piston with a 5.7" (350) rod. 400 crank. 76cc. (stock) heads

    Stock 400 pistons or would I need custom ones with a different pin location? I am guessing the slight longer 5.7 rods would provide alittle more bottom end??
     
  13. You'll need special pistons but they are readily available.

    However, if you are on a budget the stock 5.565"/400 rods work just fine. Going with the stock rod you'll only have to purchase pistons.
     
  14. As long as you need a crank and you already have 2 bad rods, I'd go with the 350 rods and matching 400 postons with a new aftermarket crank. The reasoning for using the longer rods isn't necesarily for high performance..it's also for longetivity. The longer the rod, the less angle on the rods through the stroke. The 400s short rods put a lot of side loading on the pistons, wearing the bore and the pistons. The longer rods lessen that side loading. YOu can also use Olds 6 inch rods but they require machining which may take a bite outta your budget. I believe stock pistons and 350-rod pistons are about the same price and you're gonna need pistons anyway. 350 chevy rods are cheap-cheap...same or less than stock 400 rods.
     
    Last edited: Oct 11, 2012
  15. Yea you're right! I forgot about the bad crank AND 2 bad rods. You may as well go out and buy a complete rotating assembly with the 5.7 rods.
     
  16. torque plate = Yes
    Careful with the 350 rods as #2 and #6 will come into contact with the camshaft !!
    Scat makes a nice rod with Cap-Screw Fastners >>>>.
     
  17. SCAT stock stroke cast crank for the 5.7" rod, EXT balance like stock.
    SCAT 5.7 4340 I-Beam rods.
    KB Hyper Pistons for 5.7 rod, DISHED for approx 9.8:1 Squeeze w/64 cc chamber.

    You didn't even spend $750 yet, use the rest for machine work, torque plate hone, check align hone, and balance.

    You will have 1 SWEET piece, should last a lifetime and you will be VERY HAPPY!!!!!!!!!!!!!!!!!!!!!!!!!

    All the best, TR
     
  18. If you have heads w/ 76 cc chambers, go with the flat top slugs for a 10:1 approx. squeeze ratio. Pistons are even $30 cheaper than the dishes, buys some beer and steaks for final assembly day.
     
  19. Large journal 327 crank, short stroke 350.
     
  20. Dan, I don't know you but I don't think you'll be happy with the short stroke 400. I think you will getting into build territory that you won't really be happy with. Beside theres no replacement for displacement. Build your self a torquey 406, torque is what gets you from point A to point B the fastest, and will be the most pleasant to drive, even with the lumpy cam. Besides it will more than likely be cheaper this way as well.
     
  21. True dat! I bult a 406 for my 3350 LB 50 chevy with a saginaw 4 speed [low 3.40 1st gear] and 2.29 gears with a semi-lumpy 292 degree cam...loved it! Had enough low end grunt to be very pleasant to drive on a trip and the lilght weight and 3.40 low gear made it nice to drive in town...don't go totally radical on the cam on one hand, on the other the big cubes will tame-dowm a lumpy cam..I was totally happy with my 292 cam with 110 LSA.
     
  22. Thanks Rocky, I know I'm a prick sometimes but I truly mean well and only want to help out the guys and gals here on the HAMB.
     
  23. I run a 40 over 400 in my old.vega wagon...stock slugs and a big cam in the beginning...rpm manifold...torque out the ass....wasn t too many locals.who wanted.to bust em off aroind here...generally was.some yahoo with a strip built car would come around to run....got tired.of.those.guys....freshened.it up and dropped.a.baby blower.on it...5 Years drive.to and from work.daily..till the.snow flew....the hilborn scoop hangin out of.the.hood discouraged most of the locals...and the whin..cheap...easy...dependable...kills.me.every tome.i.hear about.rod.changes...bad.cooling...deck.cracking is a common.issue...but only on certain casting numbers....the 509 castings do.t have this issue..issue mines hangin on the stand next to me right now....i keep toying with the idea of making it the play motor for my fiat topolino...in the end i had 628 ft lbs of.torque....n just u at.592 ft.lbs of.horsepower....never hardly ever revved it past 3800 rpms...the torque was working peetty strong by then....and i was generally ahead of anything by at least a vega length:cool:

    Sent from my DROID device using the TJJ mobile app
     
  24. You can buy a new set of Vortecs from Summit/Jegs for $650.00 complete with .470 lift hyd springs, not sure you can get sportsman castings bare for that. Resurecting a set of pre Vortec production heads will cost near that, and Vortecs will smoke em.
     

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