400 Non Stroker Build

Big Block A body Tech

  1. rumblefish360

    rumblefish360 Getting closer FABO Gold Member

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    With the raised height of the 440 slug sitting only.027 in the hole, as the guesstimate is above, with a 72 cc Edelbrock head, that inexpensively price unit, you could get better than 10-1, 10.5-1 *I think.* But this I don’t know for sure.

    I have two 400 blocks I’d like to get to one day soon. Using one as a stock stroke would it bother me.
     
  2. rumblefish360

    rumblefish360 Getting closer FABO Gold Member

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    I’m not sure what Cali’s lowest grade is, but I think this might be lower. I could try cat piss I guess????
     
  3. rumblefish360

    rumblefish360 Getting closer FABO Gold Member

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    At a grand a set, WOW! But yea, that’s the only way I know of unless someone out there makes them. This IDK. You can special order them from KB, but IDK the price for that special order.
     
  4. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    Then what to do for valve reliefs? IF the pistons are thick enough, it presents extra cost that could have gone towards custom pistons.
     
  5. rumblefish360

    rumblefish360 Getting closer FABO Gold Member

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    I just used the replacement piston as an example. The site showed a solid flat top and a 4 valve relief piston.
    I didn’t bother with the high performance pistons.
     
  6. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    Right....and they'll fit. People have done it, but it somewhat limits the camshaft. If they're thick enough for reliefs to be cut......didn't Hughes or some other company actually RENT fly cutters at one point?
     
  7. 33IMP

    33IMP Well-Known Member

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    I have seen some icon/KB pistons for mopars with HUGE valve reliefs. If you go to piston details , icons site says how deep the reliefs are.
    Isky used to rent flycutters. Ive seen someone selling them recently too. We did a homemade pair, a few years ago. Welded a carbide cutter to an old intake and exhaust valve. Turned out we only needed a small nick on the exhaust side of a cast piston, to get a 312 .590 purple shaft in it. Ran surprisingly well for a low compression engine.
     
    Last edited: May 5, 2021
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    • Edorion

      Edorion Active Member

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      Chrysler B-series 400 - Hemi Power At Half The Cost - Car Craft Magazine
      I bought the short block, topped it off with some mildly massaged RPM heads and PRW 1.6 rockers, and an Offy tunnel ram, made 489 ft/lbs, 472 hp. Life's kept it off the street and I've got a rocker correction kit and am going to swap a different cam to be more friendly for the EZ EFI system. Ended up with 9.5:1 CR, I'll probably get the heads milled to pick it up some.
       
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      • forphorty

        forphorty Well-Known Member

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        About 20 years ago , I built a low buck 400 with 440 Ohio cast 72-78 replacement pistons. .060 over in a .040 over 400. About .010 in the hole IIRC. No valve reliefs , but plenty of room with the Comp XE268. Took a chance ( not smart) and didn't balance it either. No vibrations and it's still alive today. the forged Speedpro 2388s will work if you can find them cheap. Any of the low comp 440 pistons may be hard to find for a reasonable price in the required oversize due to the fact there is not much demand for them . There was a guy on Moparts that said he used the 2266s with an open chamber head and modified the pistons to clear the head and had valve reliefs cut. If your block will clean up at .010, Summit has the Silvolite low comp cast 440 piston in .030 over for cheap (at the moment). DODGE Silvolite Pistons 1276-030 Silv-O-Lite Cast Pistons | Summit Racing This is for educational purposes only. If'nitwereme, I would probably put a stroker kit in it.
         
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        • Bronson77

          Bronson77 Active Member

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          Would those be a better choice than the KB240 pistons??
           
        • Max1196

          Max1196 Well-Known Member

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          Is your crank "cast" or "forged"? This makes a differance in the piston skirt to counterweight clearance when using the UEM 1276's or the FM 424NP's.
           
        • MOPARMAGA

          MOPARMAGA FABO Gold Member FABO Gold Member

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          Kb240 I believe, you'll probably need to deck the block .020 to get it straight & flat so they will be helpful compared to stockers, another is the low compression 440 pistons 1.928 ch.
           
        • MOPARMAGA

          MOPARMAGA FABO Gold Member FABO Gold Member

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          You can use my 2 year old cat as a nitrous kit, that boy loves to spray
           
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          • MOPARMAGA

            MOPARMAGA FABO Gold Member FABO Gold Member

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            I built a 73 400 in my 73 charger back in highschool, I used the MP 474 cam (which I would buy comps version), put headers on it, windage tray, shift kit, mopar dual plane intake & 2 inch spacer, Carter 625 carb & put a 3.92 gear in the 8.25 rear.
            I didn't dyno it or anything but the 1st time I raced the car it ran 17s & after all that it ran a 14.9. Fwiw, they are responsive. It could've been better with a converter, better carb & a sure grip but back then I was a parts changer not a mechanic & I was broke. I'm building a 400-470 for my dart now...i wanna go fast
             
          • Bronson77

            Bronson77 Active Member

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            It has a cast crank.
             
          • YY1

            YY1 Well-Known Member

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            9.5:1 is a pretty good ratio to start from for pump gas.
             
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            • Bronson77

              Bronson77 Active Member

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              400 BB Mopar budget dyno test***MORE PICS

              I think this looks like a good build? I’m assuming those were the KB240s and I would more than likely run Stealth aluminum heads. So it should make good power and be streetable and run on pump gas. Given the car is heavy I will obviously put lower gears in it. If I wanted to go on the highway for a trip or something no biggie to swap pumpkins. Think I will base the build off of this. I’m assuming the aluminum heads would help????
               
            • Bronson77

              Bronson77 Active Member

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              I’m assuming it would be better to run the Stealth heads over 906/452 heads? The 906/452 would have 2.08 intake where the Stealths come with a 2.14 I believe plus there aluminum and probably flow better.
               
            • MOPARMAGA

              MOPARMAGA FABO Gold Member FABO Gold Member

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              If you can find the pistons, they're 1.928 ch which is a bit taller than the kb240. The 440 pistons are just cast not hyperutectic.
              Chances are your 400 will need to be decked quite a bit to get squared up. Alot of blocks end up around a 9.70 deck height.
              The 240s would be sitting around .030 under the deck. That will help a bit. With pistons that far below you won't have to worry about valve clearance. I assume you won't be running any moderate-big cam
              (Otherwise the car will be a turd).
               
            • MOPARMAGA

              MOPARMAGA FABO Gold Member FABO Gold Member

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              Yes but with a street car especially a large C-body you're going to want port velocity over high lift flow numbers. So if you do go with stealth heads you won't want to run over a 750. The new edelbrock carb will probably be best. I ran 452 heads on my 400 & it did very good. It was a daily driver
              A cam in the high 220s low 230s with a good stall will be fun. 3.55 gears would be a good all around gear also
               
            • Bronson77

              Bronson77 Active Member

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              The thumpr is 227-241@ .050 and

              480's-.490's lift. But with stock rockers lift is more like .450's and .460's.
              LCA is 107
              This is the cam used in the link I posted above. I believe IQ52 did that build?
               
            • MOPARMAGA

              MOPARMAGA FABO Gold Member FABO Gold Member

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              Yeah that will be good. That will shake the dirt off the paint
               
            • rumblefish360

              rumblefish360 Getting closer FABO Gold Member

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              Depends on how much more camshaft you out into it. Here’s the thing, head vs head the numbers favor the aluminum head. On low lifts, it’s not a huge deal, but yes there’s power to be made, not much. Add duration to any head and the power goes up. Back to the head itself, the aluminum will start making more since the flow rate is higher, but again, unless there is a not meaningful amount of duration added, the gain is low but still expanding at a greater distance on the dyno read out. Add more lift to get into the higher flow rates where the flow differences really start to show and then the power divide really starts to increase.

              Basically, if your not taking advantage of the heads capabilities, your wasting time, effort and money. You can do really well with a well prepped iron head. Do not be fooled otherwise. If you’d going to go aluminum, take advantage of it!
               
            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              Maybe. Maybe not. It all depends on camshaft choice. He can still have detonation issues on 87 with the "wrong" camshaft for that static compression ratio.
               
            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              That's all dependent on who does any port work.
               
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