Building a hot 360

Discussion in 'Small Block Mopar Engine' started by 1973dusterkid, Mar 25, 2018.

  1. 1973dusterkid

    1973dusterkid Watch This

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    Ok so I am wanting to build a hot 360. It’s going in a 73 duster 4 speed 8 3/4 with 4.10s and a spool. This is a street/strip, I am ok with it being a handful in the street. Car is manual steering and brakes.

    Now my power goals are around 425-450 with equal torque and a nasty idle. Yes I know that kinda hampers low end torgue, but who doesn’t love a nasty idle.

    I am starting with a 71 model 360 block that has factory crank and rods with flat tops in it now. Has a pair of 2.02 valve J heads, and 340 intake. Has a voodoo cam, I think it was the one with .509 lift. Holley 750 with a set of longtubes runs good but has a lot of blow by, so time for some work.

    Looking for input on a good set up would like to keep my heads and port and polish them. Rpm air gap intake, thinking I want to try the demon 750 carb mechanical secondary. Would like to keep compression around 9.5 running 93oct. Don’t know which cam to run need input and not sure what pistons to run would like to keep the pistons hyper for cost. Also looking at Ingtion systems would msd be best.
     
  2. replicaracer43

    replicaracer43 Old school member

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    Your plan as-is sounds pretty good!
     
  3. 72Dart6pack

    72Dart6pack Harder Better Faster Stronger.

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    $6000 later you will meet your goal... Lol
     
  4. rumblefish360

    rumblefish360 so close yet so far away

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    For a short block rebuild, I love ether the KB-107 or the Speed Pro 116 hyper slugs. At a zero deck height with a .038 head gasket, there approx. 9.8-1 in a 70cc J head. If the piston doesn't sit at zero deck, which it probably will not, you'll be in good shape. I ran this 360 combo (same as yours above) on 93 octane and a Purple 292/.509 cam. No problems.
    Car was a '73 Cuda, 4spd, 4.10's, 28 inch tire.
    If you get this well tuned, you should be able to run low 12's. Better if your a light weight car.
     
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    • doogievlg

      doogievlg Well-Known Member

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      My engine is going together here soon with the same goals.

      360 .30 over
      Speed pro flat tops and edelbrock heads
      10:1
      Hydraulic roller cam that is .522 lift
      Performer rpm intake and 750 dp
      Tti long tubes.

      Dyno day should be in a couple weeks so I will try to remember to post my results on this thread for you.
       
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      • Dfr360cuda

        Dfr360cuda Well-Known Member

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        I'm planning the same thing. Probably will take a little longer.
         
      • Abodybomber

        Abodybomber Breaking street machines , since 1983.....:)

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        Rob " Rumble " ..,nailed it...
         
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        • 1973dusterkid

          1973dusterkid Watch This

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          With me in it, it’s 3560 and the your saying have the block zero decked with the kB postions?
          What kinda can would you recommed?


          Really wish I could go roller but not in the budget.
           
        • Inspector71

          Inspector71 Well-Known Member

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          Can't wait to see how they run. I have a 68 Barracuda that came with a slant six. Front end set up with BB torsion bars and 15" disc brakes. Suspension control arms 100% new. Friend wants me to do the Hemi swap. This is a street only car for cruising and I'm not sure I want the hassle. Local machine shop can take care of the 360 block, friend can assemble it. I'm leaning toward 360 since I already have it. Any opinions?
           
        • rumblefish360

          rumblefish360 so close yet so far away

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          No, I’m not saying zero deck the pistons. If I did I would have said so and not beat around the bush about it.
          I told you what the ratio would be if you did which is 9.8-1.

          Solid flat tappet lifter

          I missed on the ignition.
          MSD is fine. I run the MP Chrome box or the FBO box. Recurved OE vacuum advance distributor.
          Pace Performance has a ready to run distributor nearly identical to the MSD ready to run at a way cheaper price.
           
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          • Bill Crowell

            Bill Crowell Well-Known Member

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            Don't make the same mistake I did: not understanding that you've got to have quench. Make certain that you've got your quench all figured out.
             
          • rumblefish360

            rumblefish360 so close yet so far away

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            You don’t have quench. Either build with it or just forget about it and proceed forward. With his open chambered J heads, building a quench engine would require different piston and a high compression ratio would result.
             
          • 1973dusterkid

            1973dusterkid Watch This

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            Now what would be a good cam recommendation? I have a hydraulic flat tap now.
             
          • rumblefish360

            rumblefish360 so close yet so far away

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            Again you ask a question that is very broad and I’ll not give a broad answer again. How about a question for you! LOL!

            What is the intended purpose of the car and what would you say is the street/strip percentage?
            What size tire are you running?
             
          • 1973dusterkid

            1973dusterkid Watch This

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            60 percent track 40 street 27in tire on street 28 on track
             
          • rumblefish360

            rumblefish360 so close yet so far away

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            I’d look at something like a MP 296/.557 or equal like cam since your running J heads.

            If there not already ported, make sure when the are you have the springs needed for the intended cam to be used.
            And make sure the Head porter knows you need to have the lift clearance. iE; Wha cam your using.

            Also, if not already done, I would consider moving to a 1.6 rocker (with the MP shaft for almost .600 lift.) on the fully ported heads to get some air and fuel moving. Once you start Devi get that thing up she’ll wanna really go nicely for you.

            This set up should be able to bet you into the 11’s just fine.

            Well tuned engine, shifting like a demon on a mission, chassis worked out... yea, your in!
             
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            • doogievlg

              doogievlg Well-Known Member

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              Chassis worked out is the key.
               
            • 1973dusterkid

              1973dusterkid Watch This

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              Well rockets ain’t in the buget yet but there coming
               
            • fishmens67

              fishmens67 Well-Known Member

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              nice recipe ! the op asked he got it.
               
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              • RustyRatRod

                RustyRatRod Just another dumbass. Technical Editor

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                I have a nice NIB Crane grind in the for sale forum that will more than meet your needs for a camshaft.
                 
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                • AJ/FormS

                  AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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                  If I may, For a dual-purpose machine; Stick some hi-flo aluminum heads on it, pump up the pressure and run a cam at least two sizes smaller. That got my 3467# combo to 93 in the 1/8th,with a 230cam, on 87E10, with a nice safe street tune. Make sure you can get street headers for whatever head you buy.
                  And that's my opinion
                  But I sorta like Rumbles combo in iron
                   
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                  • rumblefish360

                    rumblefish360 so close yet so far away

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                    Thanks AJ. I figured, possibly incorrectly, that stepping up from the 12 second Hyd. Purple 292/.509 would be a direction intended as well.

                    The cost of ported iron heads is or should be very close to OOTB Edelbrock heads but with better flow. Hence the argument that always follows between metals.

                    Ether way, the OOTB Edelbrock heads with this combo would need minor work as a min. starting with clearances for the added lift with the 1.6 rocker @ nearly .600 lift. Mo-money spent and zero flow enhancement.

                    Of course there is also the use of a different cam that has a smaller lift fitting the Edelbrock head....
                    .575 is a decent bit for the street.

                    Ether way, iron or aluminum, tasters choice. Know your equipment and work it,.
                     
                  • AJ/FormS

                    AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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                    For a streeter,one thing I especially like about aluminum heads is you almost have to really try to screw up the compression to get into detonation.
                    And I agree, about cam lift.
                    ______________________________________________________________________
                    I'm running .549 in /.571 ex, with 1.6 arms; theoretical/not measured, on those Eddies.It's an old Hughes HE3038AL; 276/286/110; spec'd to be 230/236@.050. I too run the KB107s but at .005 pop-up +/- .001, and the 039 gasket, and the AirGap, and the Milodon roadrace pan.lol And it's a 71 block with 1969 bushed rods from a 318.
                    That cam is super tame, with very little lope @700. And I can drag it down to 500/550 with the clutch, allbeit it runs better down there at about 5 to 7 degrees idle-timing.
                    If there is a next cam, the fourth, it will be a more aggressive solid; building more pressure; not for power, but for fuel-mileage. I'm gonna rotate the events, and pull more extraction-degrees out of it. I kindof screwed myself tho, cuz with a max of .006 pop-up now, I'm not sure if I wanna run the .028 gasket as I did once before with pistons down tho;.005,lol. I guess I'll see if I can shave a lil off the top of the tall boys....Yeah I know;I could continue with the .039, but you know me, looking for the edge........
                    Besides, just once in my life I wanna be able to say; "hyup she's running 190psi front to back and side to side, you wanna race?"i
                     
                    Last edited: Mar 26, 2018
                  • rumblefish360

                    rumblefish360 so close yet so far away

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                    For street/street-strip engines that see mostly street duty. Best bet all around is a zero deck height to a very very low Negitive deck height. Allow the head gasket to make the final ratio come in.
                     
                  • sireland67

                    sireland67 Well-Known Member

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                    X2 I adjusted the head gasket thickness when I took the completed motor I built for my Duster, and put it in a 4x4, I also changed the cam out for a more torque related roller.
                    It worked out great, my cousin and mopar fanatic friend say the old truck idles nice, and opens up like a stock car.
                    10.81 compression 175 psi, runs on pump gas 93, but when pulling a heavy load, I dump 5 gallons of 115 in the tank, which I can buy at the local truck stop thru the pump.

                    8Sf1gb.png

                    Comp cams desk-top dyno, the engine acts just like the print out, enough for an old work truck.

                    ad2Ofd.jpg
                     
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