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Projects 400 Small Block Chevy Engine!

Discussion in 'The Hokey Ass Message Board' started by nathaniel c robitzsch, Mar 11, 2016.

  1. ANYTHING! You might have seen that I had posted this forum before, but it was deleted by the website because we got off topic. PLEASE tell me everything. From the last post I have heard MANY stories about the good and the evil. I have been taught many things from the last two threads, but keep the information coming. Tell me everything. Where you got the info, your past experiences with the engine. I am aware of many things with the engine now. I know that the engine is Siamese (there are no coolant holes in between the pistons?), Core shift is very common in the engine, it was not designed to be a racing engine, but instead to be a torque heavy machine to power large trucks. APPARENTLY the 2 bolt-main blocks are better at taking abuse that the 4 bolt-main. The SBC 400 needs the 400 flex plate and harmonic balancer(Not sure on this)? I also know that if you were to bore the engine stop at .030 (Not sure why, but everyone has told me this) People tell me that the steam holes are not needed, but I find that kind of hard to believe. If someone can tell me why that is, I'd be very grateful. Thank you all, and hope to see many posts!! :)
     
  2. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,143

    DDDenny
    Member
    from oregon

    Nathaniel
    Glad you aren't discouraged by the thread getting closed??? aparently I was unaware of this. Really good to see that you are still enthused, and focussed.
    This period of your "learning curve" will really pay off. I also think back to the way that I (and most of us old dudes) gained knowledge about cars and I have to say that this form of gathering information compared to just reading about it in a tech. training environment will help motivate you and not be so "dry" and structured like in a classroom.
    That's not to say this is a replacement for higher learning, because you still have to get the basics down. Your articulation in this new thread tells me that you were paying attention throughout the first thread and were "taking notes", this motivates the rest of us to follow your journey and stay involved.
    This whole discussion was created by you, so you should "own it" and be responsible for it's content and the direction it goes. It's easy for us (me) to wander from the subject, but if you are paying attention you will still find valuable information when it strays into "off topic" land. If you are concerned about the thread detouring; just say so, we won't take it personally.
    Doug
     
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  3. Frank Carey
    Joined: Oct 15, 2009
    Posts: 574

    Frank Carey
    Member

    The 400 is externally balanced. This means to get everything into balance the designer of the engine had to add a weight to the flex plate and also to the balancer. When my flex plate cracked I was able to buy a new one with the weight on it. I didn't have to rebalance everthing.
     
    Dan Hay likes this.
  4. since it is an O/T engine, the internet is a great source of info........
     
    hrm2k likes this.

  5. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,530

    Dan Timberlake
    Member

    I think the requirement for steam holes in the heads is modified by the engine's intended use.

    No first hand experience yet, but I think if there will be some low rpm service ( any realistic street application, and many "high performance" applications ) the holes are needed, just like Chevy did it.
     
  6. A small block Chevy is hardly off topic. There's enough to read here about that engine to keep you busy for weeks.
     
    hipster, slack, Russco and 1 other person like this.
  7. Thank you man! I was just frustrated they shut it down about that. Thank you! I hope you and many others stay on the thread to help me out!!
     
  8. So there is no need to use the stock flex plate and balancer? Or use it just on the safe side?
     
  9. I thought the same. I will be using this in a street car, so I believe that!
     
  10. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    You will need 400 balancer and flex plate.
    You can buy replacements.
     
    Dan Hay likes this.
  11. Oh ok! Awesome! Thanks
     
  12. New 400 SBC thread. COOL!:D
     
  13. deucendude
    Joined: Oct 31, 2008
    Posts: 667

    deucendude
    Member
    from norcal

    Small block size, big block power. Have one in a 48 woodie since 92 and runs like stink. Lots of miles in a 32 and mine don't overheat. The heads have been drilled. I have a spare under the bench just waiting. I like them.
     
  14. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,143

    DDDenny
    Member
    from oregon


    Not sure why the previous thread was closed, glad it has resurfaced.
    The young man that started the first thread and this one deserves to have this one stay focussed for one simple reason: he came here for information and to be a part of this community. I for one learned some things from it and was really enjoying the input from most of the participants.
     
  15. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 3,375

    GearheadsQCE
    Alliance Vendor

    I did one with and for my son. His is +.030 on the bore and a .080" stroker, giving 415". This was done by offset grinding the crank to 2.00" rod journals. With a set of Dart 2 iron heads and a 300 degree hydraulic cam, it will smoke the tires as long as you keep your foot in it.
    Really cheap and done before off the shelf cranks were so common.
     
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  16. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377

    indyjps
    Member

    SBC and especially 400's, everyone's got a different opinion.
    Good cores were difficult to find 15 years ago when I bought a couple to stick under the bench. With so many going LS, maybe some of the hoarders will free up the stash.
    See what you can find to work with, all you need is the block and maybe the factory crank. There was good info on core shift on the last thread, choose your block carefully and you will save a lot of machining work later.
    A basic recommendation for a street engine. 400, .030 over, factory crank, hypereutectic flattops on a 5.7 rod, balance assy. Deck the block, vortec heads, modified spring pockets, pinned or screw in studs. cam depends on combo. This basic short block combo can be a pulling truck engine, 400+hp strip engine and anything in between, cam, head, induction will decide.

    If you wanna go racing it just depends on what you want to spend. 434 stroker crank combo you almost have to run small base circle cam and specific rods help with that, there are exceptions, 415/420 stroker is more forgiving on small base circle cam requirement.
     
    Last edited: Mar 12, 2016
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  17. Yes sir! I really enjoyed it too! It really was a learning experience!.
     
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  18. How old is your son? Sounds lucky!! xD
     
  19. Yes! I agree!! What are "Hypereutectic flattops"? Balance assy? I heard decking is no necesarry unless it is uneven? Please explain. Instead of Vortec Heads, what about the Trick Flow Heads? What modified springs?
     
  20. I want to have a powerful street car. The car it is going in is already fairly lightweight, and is in the paint shop now. Can't wait for it to get back, but in the mean time I want to start on this. I want my car to be strong enough pull from a stop light and beat the z06 sitting next to me ;)
     
  21. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377

    indyjps
    Member

    My apologies for jumping ahead too much. Hypereutectic flatops are flat no dome pistons usually with 4 valve reliefs cut in the top. They are cast pistons but a better cast material than a regular cast piston. An alternative would be forged pistons that cost more. A forged piston is superior but you need to run larger piston to cylinder wall clearance. If you're not racing or turning high rpms, a hypereutectic piston is a very good choice.
    Balanced assy is a spin balanced rotating assembly. Crank pistons rods are weight matched then spun and weigh is added or subtracted on the crank.
    A stock 400 has a 5.565 inch connecting rod, a 350 and others have a stock 5.7 inch connecting rod. Using a 5.7 in rod in a 400 reduces side thrust into the cylinder wall. This is a common change and piston manufacturers make off the shelf pistons for a 5.7 rod 400.
    A 400 external balanced. Meaning the harmonic balancer and the flywheel have weigh added, harmonic balance it is cast in, flywheel had a strip of weight welded on.
    A 350, 327 etc are internal (neutral)balanced.

    When you go to spin balance a 400, you can choose to keep it external balanced, recommended on a stock crank engine. If you buy an aftermarket crank you can go to neutral balance.

    If you use a stock 400 crank, harmonic balancer, flywheel, then add 5.7 rods and aftermarket pistons, you should have a machine shop spin balance the engine to account for the weight differences in connecting rods and pistons. I'm just touching the surface here, lots of tech on balancing.

    Trick flow heads would be great of you want to spend the money.

    Vortec heads are not traditional, but neither is a 400. Stock vortecs will out flow any other factory chevy head in mid range where you spend the most time driving. The issue is the valve spring pocket is a different size than traditional sbc springs, and youre limited in lift to around .470 on the cam before spring bind. A set of stock vortec heads can have the spring pockets machined to accept regular sbc springs and allow up to .500 lift. Higher lift than that you should be looking at aftermarket heads anyway. Another option with vortec heads is to use a beehive spring, it's conical wound and allows higher lift before coil bind on an unmodified set of vortec heads.

    Same advice as before. Try to find a good 400, It may be difficult or expensive. A 350 block with a 400 crank makes a 383, they are very good engines and the aftermarket offers new cranks and balanced assembly ready to go.

    I'm not being critical, but from your questions, a crate engine may be a good choice over a full rebuild. We all gotta learn somehow though. Let us know what you find.
     
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  22. Hollywood-East
    Joined: Mar 13, 2008
    Posts: 1,993

    Hollywood-East
    Member

    A stock re-ring,valve job, cheap "z28" spring's, lathe turned locks(cheap insurance) a decent cam...Will move a light car pretty impressive! Had one when I was a kid in a Gutted 63 Chevy II, tr1 tunnel ram, Vega converter(2800) a 350 trans., 3:08 out back, would pull the front left wheel Hi enough to clear a beer can, Fun car in hi school.. Good luck!
     
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  23. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377

    indyjps
    Member

    So plan for a street strip car that will run a mid 11 at the track.

    Assuming the car is OT so let's just talk, weight, transmission, gear ratio, what kind of rear suspension or traction device.

    3000 lb car you'll need 450-500 hp depending on a lot of variables, chassis and tuning can make big differences.

    Look at a 383 or 406, forged piston, aftermarket heads, I'd go AFR airflow research, before trick flow. There are a lot of vortec based aftermarket castings with larger runners that will get you there also.

    A basic set up for a low 11 sec car would be 3000 lb car, 411 - 430 gear, 383 or 406 with forged pistons, balanced, aggressive cam (hydraulic lift 290-300 duration, .550 or so lift), 750 holley double pumper. 3500-3800 stall speed. Good traction and chassis set up. There's a lot of tuning and factors to run the number, It won't just assemble and be a top runner, you have to spend time dialing it in. More cam, more stall, more gear are always options, you have to match up your power train then tune the hell out of it. Step up to roller cams and associated cost and it will be a better combo.

    Start pricing this stuff out, let us know what your set up is now.


     
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  24. cj92345
    Joined: Jun 17, 2009
    Posts: 164

    cj92345
    Member
    from so-cal

    I just bought a used 434 engine (400) block, made 680hp cam is .725 lift solid roller, brodix heads dominator carb, ect,ect,..i'am going to tame it down with a .550 ish cam, 850 carb,dump the gear drive, rev kit and stud girdle, (wont fit in my hot rod with tall valve covers) hopefull get down to around 475- 500hp, my block does have the small cracks from upper steam hole to head bolt, it has head stud's already and going to keep them, from what I've read these cracks are not a deal breaker, just use sealer on the treads.....my car is 2400 lbs, power glide with 3800 converter 3.90 gears, I don't want to go any faster than 11.50, so still may need to put on a adjustable e.t genie.
     
    Last edited: Mar 15, 2016
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  25. Wow man! That's great information! Thank you! I would LOVE to start with a crate engine, but I don't have the money to start with a crate engine. I'd also like to learn how to rebuild my own engine. That's the only reason I am using this engine instead of a crate. I am going to get it saturday. I know I should look for Core shift, if it is 4 or 2 bolt main. What else should I be looking for??
     
  26. WOW! Sounds impressive!
     
  27. T
    The car is around 2,200 with the strait six in it now. Guessing with the 400 in it, it will be around 2,600-ish pounds.
    "3500-3800 stall speed"? You mean Idle speed??
     
  28. Sounds like a beast man! you said put sealer on the cracks and that should be fine? Sounds fairly easy to deal with those cracks!
     
  29. Hollywood-East
    Joined: Mar 13, 2008
    Posts: 1,993

    Hollywood-East
    Member

    He's referencing "stall" speed, You'll notice I mentioned mine at 2800, that's the rpm before its time to"Go"! Ever wonder how a dragster sits at the line almost wide open throttle, it's on the torque converter, they come in All ranges, which is relitive to cam, intake,rear gears, an weight of car...
     
    Last edited: Mar 15, 2016
  30. H380
    Joined: Sep 20, 2015
    Posts: 483

    H380
    Member
    from Louisiana

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