383 cam advice?

Big Block A body Tech

  1. HP2

    HP2 Well-Known Member

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    Hi everybody!
    Looking for input on my matching 71 Charger Super Bee engine.
    Let's start with to say that I'm somewhat on a budget. Plus I like doing the job myself so the engine will not leave my workshop until test drive.
    I like being cheap but I want things to be properly done so I can rely on my engines when they are finished.
    I have other projects I need to finish before this one so I'm just setting up the plan and gathering parts right now. Car is at my body guy's place and I hopefully will get it painted so I can have it finished by next summer.

    Goal is to get a strong torque engine so I can keep the original converter and 3.23's. Lots of power directly from bottom makes cars fun. Power on tap is beautiful.

    I've been thinking of how I should put it to make you understand of how I see it.
    If you'd had a chance to log the throttle position for a season on a street driven car (such as a 71 'Bee) I'd swear you never go WOT more than a few percent. Probably very very few.
    The idle portion would be quite a big number, depending on the traffic situation at your location of course.
    If I make a wild guess of the throttle opening you actually DRIVE your car I'd say it's mostly between idle and half throttle. At least that's how I drive my cars. Using a set of 275 BFG takes only a few minutes of pedaling! LOL

    The engine I'm planning to build is for a driver.
    Looking at dyno numbers are always fun, but I don't know anyone who puts his street car in gear, floors it from 2,500-3,000 and wait 'til the power ends. Well, if he goes to the track, but that's a completely different story.

    A dyno can't give the information of how the engine works in a street car. How responsive it is, and what will happen if you give 3/4 throttle at 2,000 rpm's. A chassis dyno can do it better, but not fully.

    I want my street driven 383 to be long lasting, ready for long trips on winding sideways or a trip to the town to lay out some smokescreens. No unburned fuel wiping off the oil film from the cylinder walls.
    I want it to be snappy and happy, have muscle car characteristics with a bit lumpy idle and grunt from bottom so I don't have to wait for it to happen.

    If it wouldn't have been a matching car I would have used the 67 440 I have sitting, or maybe built a 400 stroker. It would have made it easier to achieve my goals, but that's not an option now.
    If I had too much money or lived in the US I would have considered building a stroker out of the matching block, but that's too risky with today's situation. Shipping overseas sucks these days...
    As said before, a 383 is not the best start - but now it has to be a 383, and I will try to make the best of it.


    I'm gonna try to use the parts I have and do it all by myself at home. Do it and build it like I describe. Be painstaking with the details, jetting and timing.

    Talking about torque converter, I do hope it still has the correct HP 10 3/4"! It's still in the car so can't check for the moment, just came to think of it. IIRC that converter stalls around 2,200-2,500 behind an original 383?
    Well, with a stall at that level I guess it's no longer need for a real low end torque engine. Please, keep on reading and I'll give you the basis for my build.
    Need vacuum for the power brakes but that should not be an issue with the characteristics I'm looking for.

    I will port the 906's using the old templates. Cleaning up the bowls, straightening and cleaning up a little. Do a basic 3-angle valve job. Mill them if necessary to achieve correct compression ratio. In Sweden we have 93.5 octane at the gas station so around 170 psi cylinder pressure is good.
    The cylinder bores will clean up with honing. Maybe not 100% perfectly clean up but good enough.
    Reuse the original pistons but swap them side to side for a little more thump.
    Use a windage tray and a larger pan never hurts even if this engine rarely will see rpm's over 4,500-5,000.
    Have a nice pair of 70 440 HP exhaust manifolds lying. Will build a full exhaust 2.5" H-pipe of mandrel bent aluminized tubes. Don't know what mufflers to use. Think Flowmasters are too noisy, even the 50's.
    Was looking for a CH4B intake but since I want a spreadbore carb I have changed to a Performer. Can change again but it will be a dual plane for sure.
    Think I have an old good points distributor that I can put Petronix on. I don't trust the MP stuff anymore. Limit mechanical advance, lighter springs. And a high voltage coil.
    A spreadbore carb. Haven't looked for what I have. A 625 Street Demon would be great but might be out of my budget.
    Need to find an oval base 4bbl air cleaner to a decent price since it has the Air Grabber hood.
    Will rebuild the 727 and put in a semi manual valve body. Car is column shifted.

    Now the most interesting part. Cam selection.
    My friend has a set original 440 adjustable rockers. I think I can make him sell them to me. If so I could go mechanical cam. If not I'll stay with stamped steelies.
    Would a mechanical cam have big advantage over a hydraulic in an engine as described, or will it only make difference at higher rpm's?
    What cam would you use based on the basis above?

    I'm aware of 383's rod ratio and bore to stroke ratio. A high revving engine, not a torque monster. I know, but as I said before, I want a snappy, stong-off-the-bottom, daily driver but tire melting 383".
    My hope is that it will run mid to low 8's on 275 street tires in an otherwise original heavy 71 Super Bee... We'll see if that happens smile.gif
    To stroke it would make my goal easier but I'm not willing to spend that amount of money that comes with building a stroker. Especially not at this point. I am in Sweden and shipping parts from the US is a PITA these days. Been waiting for a box with parts shipped with USPS since mid May. It's stuck in Miami...

    What I'm asking for is cam input from people who built something similar. Anyone?

    Sincerely regards!

    I'd be grateful for your input. Thanks in advance!
     
  2. 273

    273 Well-Known Member

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    • rumblefish360

      rumblefish360 So close, yet so far away FABO Gold Member

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      You want a high mileage & torque cam that will run 8’s in the 1/8 mile in the car with a stock converter, trans, 3.23 gears and 275/60/15’s with a lump idle?


      Low 8’s in the 1/8 are about equal to 12.50 in the 1/4.
      If I have that right.
       
    • 66fs

      66fs FABO Gold Member FABO Gold Member

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      I have an original 68 383 Automatic Formula S fastback car. I put a 268 comp cams in it when it was a daily driver. Not sure why 400 ft lb of torque would not be enough for you. Ran factory 72 400 intake and TQ for years on a build similar to what you want to do. 383 donor from a Newport, honed with torque plate, just to clean up the cylinders, Speed Pro file to fit rings, 906 heads, great valve job, cleaned up the bowls, windage tray, 402 pan, hp,hv oil pump, MP distributor kit with a chrome box. No lack of low end, definately would scream if called on. It would pull 16 to 18 mpg cruising highway. I always felt the original HP cam was better. Getting ready to redo the original 383, this time I went with a Racer Brown mechanical cam. ST-1 226 degrees @.050 and .450 lift intake and exhaust, 107 degrees intake centerline.
       
      Last edited: Aug 2, 2020
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      • MOPARMAGA

        MOPARMAGA Well-Known Member

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        The cam I used in a 400 which was low compression was the 474 purple shaft, 110 lsa, sounded great & worked with the original converter, was in a 73 charger se, in high school (1997). That cam had 230 something (238?) duration @.050, id look at something like that, not a purple shaft for the wallets sake, and for longevity sake hydraulic roller. In the 234intake -238exhaust to help get out the manifold.
        Should be able to boil em. I personally like howards cams.
         
      • HP2

        HP2 Well-Known Member

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        I know it's a bit optimistic but you can always dream :)
        It should sound like a muscle car, not like a Cadillac.
         
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        • fishmens67

          fishmens67 Well-Known Member

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          Crane 683941 272 / 284 ex 454 / 480 ex
          or the next step
          Crane 683801 278 / 290 ex 467 / 494 ex
           
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          • HP2

            HP2 Well-Known Member

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            The 474 Purple cam has an old school grind with slow ramps and not much lift. Today we have a chance to get more lift with faster ramps.
            My believe is that I should stay under 220-something degrees but try to get lift as much as possible, hopefully a bit over .500 and LS around 110
             
          • HP2

            HP2 Well-Known Member

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            I'm not sure what you mean by "Not sure why 400 ft lb of torque would not be enough for you."? Did I say that?
            Anyway, the more torque down low the better. I would not try to set a limit :)
             
          • RustyRatRod

            RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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            Comp makes a Mopar lobe specific cam that's their version of the 383 Magnum Road Runner cam. It's a really good grind. The old Mopar version was ground on a 115 LSA and Comp tightened it up to a 110. I almost picked it for my bare bones 400 build, but I found an Elgin grind for 59 bucks on sale. lol Here's the Comp grind.

            COMP Cams Magnum Muscle Camshafts 21-305-4
             
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            • HP2

              HP2 Well-Known Member

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            • RustyRatRod

              RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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              • HP2

                HP2 Well-Known Member

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              • RustyRatRod

                RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                • 66fs

                  66fs FABO Gold Member FABO Gold Member

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                  That's all. A 383 is not torque challenged in an A Body, or your expectations may be different from mine.
                   
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                  • MOPARMAGA

                    MOPARMAGA Well-Known Member

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                    • MOPARMAGA

                      MOPARMAGA Well-Known Member

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                      Yes, 110 or 112 lsa, 220 @.050 is too small for a 383, your dynamic compression will be higher than your static, with iron heads yikes. I mentioned the 474 because that size lift & duration requires nothing more than a spring upgrade. You'll still have massive torque. I ran that cam with 2.76 gears with no issues, I did upgrade to 3.91 because I wanted to get going quicker. The purple shafts maybe old design but the last time I rode in a car with a purple shaft it made me smile. Over .500 Lift isn't necessary with a cast iron head. Duration is all you need to focus on. Howards has a 484 or 488 with several different durations, I think 3 different cam grinds.
                       
                    • 273

                      273 Well-Known Member

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                      Torque is all about displacement and VE% and CR, most 9 to 10:1 engines with decent heads cam intake and headers are gonna be between 1.15 to 1.25 lbs-ft per cid if you make over 1.25 lbs-ft your your doing really good. Engines between 1.35-1.45 tend to be well put together race engines high Cr 12.5 plus big roller cams and high flowing cylinder heads. Torque is basically the power of one revolution hp is all the revolutions added up. 383 can be revvers since they got big bore for breathing and short stroke for rpm, but are only that if you build them that way most street engines are gonna make peak power in between 4500-5500 depending on the build. If you build for peak power to be between 4500-5000 your gonna have a very streetable .08-1:1 hp:cid, 5000-5500 1-1.2:1 hp:cid ruffly. above 5000 gears and stall become important, which you have. Above that your more into street/strip.
                       
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                      • RustyRatRod

                        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                        Oh here we go. lol
                         
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                        • kowalski440

                          kowalski440 Well-Known Member

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                          • 496 polara

                            496 polara moparts id gch

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                            Of the Hughes and Howards cams you posted I would go with the Hughes for a heavy car with 3.23 gears and hp manifolds.

                            The hotrod article is a good example of your cam choices.That engine would have faired better with 1 3/4 headers IMO as well.
                             
                          • aaronk785

                            aaronk785 Well-Known Member

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                            I like the howards with the bigger split for stock manifolds. With 93.5 octane I'd run as much compression as I could get by with. Let the numbers guru's on here figure that for you. Comp cams 911 springs will easily handle that cam. I ran them on a comp cams 306 .555 lift solid for years and it never missed a lick even at 6500.
                             
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                            • fishmens67

                              fishmens67 Well-Known Member

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                              Pick one , either one is better than any of the others posted for a 383
                               
                            • RustyRatRod

                              RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                              The 683901 is fantastic. He did mention budget which is why I made mention of the Elgin.....obviously since I've still gotten zero response, I'm just not here so......I'll really not be here. LOL
                               
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                              • HP2

                                HP2 Well-Known Member

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                                You are absolutely correct about your definition of torque. Torque is the only thing you can measure on a dyno.

                                When I used the word torque I was careless, sorry.
                                I used it because it has been a common term when you try to depicture engines with the power in the lower rpm register. "This engine has tons of torque" usually means that the engine produces power down low. I'm sure you know all this, just took the opportunity to explicate :)
                                Thanks for the info, you learn something new every day :thumbsup:
                                Hoping to get 1 hp per cu in
                                 
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