Engine build suggestions

General Mopar Tech Discussions

  1. ksurfer2

    ksurfer2 Well-Known Member

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    What I currently have is a 69RR built as a A-12 clone. I have a 73 440 block with iron heads (not sure right now which heads), HP manifolds, and a 6bbl set up. 727 Auto trans, dana 60 rear with 4.10 gears. I am about ready to pull the motor and send it off to the machine shop.

    At the end of the day, I want a street/strip car. This will see weekend drives/cruises, but nothing long distance and fun at the drag strip. My desire is to have something that will run high 11's to low 12's.

    I do have some requirements though....I want to keep the 6bbl set up. Also I want to keep the HP manifolds. I like the look of a factory appearing engine. I would consider aluminum heads as long as I can paint them to match the engine (to maintain factory appearance).

    I am ok with a fairly aggressive cam and torque converter since the car will have to perform on the strip, but see only local street use for fun.

    With a budget of $10-12k for the build is this possible and what components should I be looking at? I'd prefer to maintain stock displacement (not build a stroker motor). Recommended compression ratio (I do have relatively easy access to 105 octane race fuel), cam specs, converter, etc? Any help would be appreciated prior to heading to the machine shop.

    Thanks
     
  2. 69 GTX

    69 GTX FBBO Gold Member FBBO Gold Member

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    Here's my 2cents. Get a pair of stealth heads. They're alum. and look stock, so you can paint them. Have a shop disassemble them and check everything.
    Get a hydraulic cam with duration in the 234-238 range @ .050 and .50-540 lift. To much duration will make your 6 bbl set up a pain to tune.
    Look at some ICON pistons with a D shaped dish to keep the compression between 9.5-10:1
    With your 4.10 gears you won't need much to make it a tire burner!
    It'll run all day long on 91 octane fuel, make 500hp and be very reliable.
     
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    • 69 GTX

      69 GTX FBBO Gold Member FBBO Gold Member

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      • 69 GTX

        69 GTX FBBO Gold Member FBBO Gold Member

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        After your engine is done, then call PTC and tell them what you have for a set up and they can then build you a convertor. It might also be a good idea to freshen up the 727, I'd recommend Cope (CRT).
        These are the people I used and they came highly recommended.
         
      • rumblefish360

        rumblefish360 Well-Known Member

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      • beanhead

        beanhead Well-Known Member

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        672.gif
         
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        • 5.7 hemi

          5.7 hemi FBBO Gold Member FBBO Gold Member

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          Love my 470! F’ing thing is a beast!
           
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          • Lefty71

            Lefty71 FBBO Gold Member FBBO Gold Member

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            I love mine too. There's just something quite right about that size.....
             
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            • 69 GTX

              69 GTX FBBO Gold Member FBBO Gold Member

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            • andyf

              andyf Well-Known Member

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              A stroker probably makes more sense since everything you want to do is easier with more cubic inches. If the machine shop is going to need to turn your crank and rebuild the rods then it won't cost much more just to buy a new rotating assembly.

              You should go with aluminum heads just for the weight reduction. Stealth heads are an okay choice or straight plug Edelbrocks. With the HP manifolds you really need straight plugs to keep from burning up the plug wires.

              I run a 512 inch big block with cast iron manifolds in my '65. You have to be very careful with the cam selection when using HP manifolds. One of the very best cams for Hp manifolds is the old Mopar 0.528 solid flat tappet. You can duplicate that cam in a hyd roller for a street car if you want. Just don't let anyone sell you a typical shelf cam. Here is my '65 on the chassis dyno. It made 485 rwhp with a small hyd roller cam and the HP exhaust manifolds.

               
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              • BSB67

                BSB67 FBBO Gold Member FBBO Gold Member

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                You've got goals, that's good.
                You can work your goal backwards to get an idea if your goal is reasonable and what it might take to get there. Things you you need to help the analysis: Car weight, track conditions, and expected suspension performance. These things can make a swing of 100 hp for your hp needs to achieve your goal. Getting to 11.8 at Bandimere in August in a 4100 lb car will be way way harder than getting to 12.2 at Atco in October in a 3800 lb car.

                I use my historic knowledge and general rules of thumb to marry up these factors. Will you be using slicks and a loose converter? Or will you run it the way you drive it on the street? These might be the same for some guys. About the best you will do with a stock suspension and a true street tire (gear has little effect with a street tire) is a 1.9 sixty ft time. And that wont be a walk in the park. Add some suspension, converter and tire, you're at 1.6. That will be about 0.50 sec in overall et, and you have not even opened the hood. Theses are general numbers.

                So here is an example:
                Goal
                12.00 sec et
                street suspension - 1.90 sixty ft.
                Track conditions - DA about 2000 ft.
                Car weight w/ driver - 3900 lb

                To go 12.0 with a 1.9 sixty, the car will need to trap at about 116 mph. To do that with a 3900 lb car at 2000, you'll need 500+ on a no BS dyno. This will take a pretty well thought out std stroke 440, but doable IMO. Like Andy says the bigger cubes really help if you are trying to keep the the low speed characteristics docile and run on pump gas

                Change the sixty ft from 1.9 to 1.6, 450 hp will probably get it done (trap speed about 111) , as an example
                 
                Last edited: Sep 7, 2018
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                • 69 GTX

                  69 GTX FBBO Gold Member FBBO Gold Member

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                  Along those lines, things like rotating mass also make a big difference. Just changing to light weight wheels and tires can shave a easy tenth off. Or you could build a mild 440 with forged pistons and a strong bottom end, throw on a 100-150 shot of N2O and reach the same goal.
                   
                • ksurfer2

                  ksurfer2 Well-Known Member

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                  Thanks...this makes a lot of sense. As for tires, when going to the strip, I will change to drag radials. I'll keep an extra set of wheels and tires so I can switch back and forth depending on street driving or going to the strip. Again, this is trying to keep the factory appearance when not at the strip. For rear suspension, I will upgrade shocks, and leaf springs, but leave the rest stock. Maybe add a set of slapper bars.
                   
                • beanhead

                  beanhead Well-Known Member

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                  One thing to note..tire spin is a great pressure release for the torque that these puppies can make. When you start hooking up hard with stickier tires is when parts tend to start breaking so make sure that all your components are up to the increased load, yolks/U-joints/rear end etc..just something to think about
                   
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                  • 747mopar

                    747mopar Well-Known Member

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                    Depends on which it will see the most of? I for one won't take many suggestions when the primary use is street... everyone suggest huge cans and numerically high gear ratios which equals a crappy cruiser. I knew mine would see tons of cruising so I built big cubes with a cam within my intended use and 3:55 gears (with overdrive). Just be sure which side your going to lean more towards before you jump in.
                     
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                    • rumblefish360

                      rumblefish360 Well-Known Member

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                      My A body small block 360 w/3.55’s & 26 tires has a 224@.050 duration cam in it. The key to power is ample air flow in and out. Spirited engine in a reasonable weight car which moves nicely.
                       
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                      • moper

                        moper Well-Known Member

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                        So it's a clone car, with a '73 440. While I love the stock look too, there's really not much rationale to retain the factory stroke. What Andy said it true - bigger means it doesn't work as hard. That translates to power at certain rpm ranges that make "street" as fun (or more so) than "strip". Power at those lower rpm equal less racey parts and less money spent. A moderate 4.25" stroke build will run around 10K, could run a flat tappet or hydraulic roller (a bit more money for that), and run on pump fuel which is a lot cheaper than race fuel and you can get it anywhere. Drive the car to the track, run in the 11s, and drive it home. No need for spare tires. I would push for the stroker long before giving a parts list...lol.
                         
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                        • 66Satellite47

                          66Satellite47 FBBO Gold Member FBBO Gold Member

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                          You are starting with the most significant constraint, stock exhaust manifolds. Even with the best acid prep they will be the most limiting factor. The 6 Pak is a bit of a pain to make work well, but it can be done and with great results. Today's rotating assembly's are so cost viable, no sense in working with the stock post '71 crank/rod stuff. More stroke does work & hurts tires.
                           
                        • ksurfer2

                          ksurfer2 Well-Known Member

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                          Thanks for the suggestions. I think I may start leaning towards building a stroker. I really don't want to ditch the HP manifolds, but that may be a concession I have to make. The 6bbl on the other hand, that stays!
                           
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                          • andyf

                            andyf Well-Known Member

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                            Why ditch the HP manifolds, didn't you watch the video I posted? You said you wanted to run 11's or 12's in your first post and that is easy to do with HP manifolds. Same with the 6bbl intake. What you're talking about is very easy to accomplish. If it was me I'd build a 505 (4.25 stroke) with 9.5 or 10.0 compression ratio. You'll want an aluminum head with straight plugs to work with the HP manifolds so that limits you but it can be done. Put a small hyd roller cam in there (240 @ 050) and you're done. You should be able to hit your budget without any problems.
                             
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