225 Max Performance Recipe?

Slant 6 Engines

  1. Nofences

    Nofences Member

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    Hi All
    I'm new here and working on my first project.
    It's a 73 Swinger. Pulled the 225 and sent body to blaster.
    I am trying to decide which way to go for power.
    Either swap the 225 for a 340 or 360 build. Or maybe build out the 225 I already have.
    Any insight on this? What HP can be realized from a 225 with mods? Any recipes for success?
    I would also like to be able to drive this on the street.
    Thanks
    Dan
     
  2. rumblefish360

    rumblefish360 So close, yet so far away

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    Dan! Welcome aboard!

    I have seen /6 engines power a car into the low 11’s. Just the engine. No blower, no turbo, no laughing gas (N02). However, streetable is also a term that is very loose and dependent on the person driving the car and what there willing to tolerate.

    On that note, the larger the engine the easier it is to make power and the ability to run quickly. IF you want to swap the 225 /6 for a small block, I honestly would skip over the stock stroke of the 340 or the 360 and make the move to at least a 4.00 crank for 408+ cubic inches. The stroker does really well in torque production, the very thing your car needs to get moving. With a good head on top, (A well ported Edelbrock head at a min.) it will produce excellent up to keep moving really well.

    There are swap kits on the market for the ‘73. Schumacher creative services is the place your looking for.

    You will alsnever need a small block transmission and a upgraded rear.
    The /6 transmission will not bolt up to the small block and the rear is probably a tiny 7-1/4.

    A big block is also possible to bolt in without to much fan fare.
     
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    • Charrlie_S

      Charrlie_S Well-Known Member

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      Slant six's have made approx 600 hp. Do you have cubic dollars. Something like that is race only, not for street. It is possible to build a slant for street use, in the 300hp range, but that is with a super/turbo charger.
      Dart270 on slantsix dot org, has a Dart 225 turbo, 200r4 trans. He drives to the track (sometimes several hundred miles) gets low to mid 20's mpg, changes tires, and runs high 12's in the 1/4.
      You need to determine how you will use the car, and what you want out of it.
       
    • UDUST81

      UDUST81 Well-Known Member

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      if youre gonna switch to a small block youre gonna need new motor tranny, rear end, headers, etc, might as well take the plunge and go big block
       
    • armyofchuckness

      armyofchuckness The Flying Valiant

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      Slant Six mods can be rewarding, but you're never going to get the bang for your buck that you would with a V8. I only recommend Slant Six tuning if you really love the engine and want to do something that really stands out at shows. If you want to go fast, go with the 340. If you want to go slightly less fast for less money, go with the 360.
       
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      • diymirage

        diymirage HP@idle > hondaHP@redline

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        this only holds true in stock blocks your not doing anything to, other then dropping it in
        the difference in core price between that 340 and 360 can easily mean you can afford to put aluminum heads on that 360, while keep the stock unported heads on the 340

        if you intend to do ANYTHING to the block, go with the cheaper, bigger faster 360
         
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        • cdnEHbody

          cdnEHbody Well-Known Member

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          Id say unless you are planning to force feed the slant youll be dissapointed with dollars spent on a streetable n/a engine.
           
          Last edited: Dec 5, 2017
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          • barbee6043

            barbee6043 barbee 6043 FABO Gold Member

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            I know a guy that runs 10.0 in the quarter with a NA slant but he has $18000 in the engine alone!!!!!
             
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            • Darter6

              Darter6 Well-Known Member

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              Yep, I spent $14,000. The guys at Indy Cylinder Head asked "Why ? You could have a Hemi for that." My response,"Because I wanted to.Anybody can have a fast Hemi,but a fast Slant,now that's something."
              Also raced it for over 10 years without fault or rebuild. So a cost of about $1400 a year.Worth it to me.
               
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              • barbee6043

                barbee6043 barbee 6043 FABO Gold Member

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                Might I add, that those of us that have run a stock 426 hemi and a stock 440, tit for tat, the hemi was only a smiggin faster in the quarter or for me, down a stetch of rural blacktop. Hemi is high priced eye candy!!
                 
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                • OldMoparFart

                  OldMoparFart New Member

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                  I used a 1965 truck 225 block, bored .100 over using Buick 225 V-8 pistons with the wrist pins sized to the Dodge pins about 12:1 comp ratio, shop made 4bbl intake w/Carter AFB 450cfm carb, the Hyper-pack cam and valve train, Clifford header w/dual exhaust, stock 3spd trans with an 8.75 rear end. Built in the early 80's
                  stock 350 Chevelles could touch it.
                   
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                  • rumblefish360

                    rumblefish360 So close, yet so far away

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                    So super disagree. The 360 is cheaper due to way more engines produced. How does 20 more cubes make an engine slower? If such is the case, then why stroke with a 4.00 crank for 400 plus cubes? To go slower?
                     
                  • Darter6

                    Darter6 Well-Known Member

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                    Yep oldmoparfart, Suprised many a V8's.
                     
                  • Nofences

                    Nofences Member

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                    Wow, thanks for all the input!! So glad I found and joined this forum.
                    I guess if I want more wow factor at a car show then the 6 all dressed up would be the way to go, but if HP and Torque are what I’m after then I should go v8.
                    340 or 360 is the next question?
                    I figure 450hp would be more than enough for my little A body.
                     
                  • MOPAROFFICIAL

                    MOPAROFFICIAL Well-Known Member

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                    It will always be 2 short.

                    Put 12.5 pistons in it, race gas,port the head to flow 190-200 cfm by .550 lift, as steetable a cam in .550 range as you can get ground and 4 barrel carb and intake run 3.91 gears with a 4 spd.


                    "Snaps fingers"

                    Seriously, you'll get pushed around with that little motor unless you make it not very steetable.

                    Best of luck
                     
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                    • cdnEHbody

                      cdnEHbody Well-Known Member

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                      Youll be able to find a 360 far easier. And cheaper, and can make the same hp just as easy. 360 had a far longer production run. A magnum 360 would be a good start. Shit a decent built 318 will boil the rubber off.
                       
                    • rumblefish360

                      rumblefish360 So close, yet so far away

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                      It’s a no brained IMO!
                      360, plentiful, cheap, 20 more cubic inches than a more expensive 340, a lot of it in stroke for more torque.
                       
                    • MOPAROFFICIAL

                      MOPAROFFICIAL Well-Known Member

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                      Even 400 hp would make most happy.
                      Factory j 2.02 heads with a 3 angle valve job , kb 107 piston 360 short block with a .500 lift 284 duration cam ,headers, rpm intake w/750 will make about 390-400 hp on a bad day.
                       
                    • Darter6

                      Darter6 Well-Known Member

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                      If you DO the Slant,people will look at you,like you are strange........Believe me I know...
                       
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                      • rumblefish360

                        rumblefish360 So close, yet so far away

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                        I don’t know what cam your making a reference to but I remember the old MP create engine. 360/380. Same as above with there 284/.484 cam. I know it dyno’d more than 380, but not sure if it creates 400. Probably did.

                        The 280/.480 cam will make about 360hp @ 9.0-1, headers, 750....
                         
                      • 273

                        273 Well-Known Member

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                        You pretty much can take any V8 add cam 4bbl and headers and beat the hp of a built NA slant 6. Head is the /6 weakest area for performance.

                        Gearing is the next problem. Smaller displacement is gonna need a lot deeper gears to be on the same footing as V8.

                        If you want any real power some kind of power adder is needed.

                        I always wanted to build a /6 but it really pointless go 360 or 408 or even 440.
                         
                      • Killer6

                        Killer6 Well-Known Member

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                        1st off, Welcome to FABO!!
                        2nd, You have three primary considerations;
                        1) Ability........what are You and the people that may/will help You capable of & willing to learn/do?
                        2) Goals..........what performance do You wish/expect? For now & in the future. Do You know?
                        3) Budget.........how much capital will You be able/willing to expend for parts, materials, & work performed that You cannot?
                        Building a Slanty that runs is satisfying, but Hp/$ it is not a bargain, even if You are only buying 3/4 of the hard parts of a V-8.
                        I built one, and am working on phase III of the same .060" over unit I started running in '88.......long before I'd ever heard of Doug Dutra etc. etc., but I did it for the
                        challenge of making one of the more lethargic contemporary powerplants out there actually run. I also swapped a cammed 318, 4spd, & 8.75 rear into My 1st car, a '69 Dart
                        Custom w/a Slanty in it.......the one I built for My other project car. I had a S*#Tload of fun in both, but a lot more work & $$$$ in the Slanty project.
                         
                        Last edited: Dec 11, 2017
                      • emsvitil

                        emsvitil Well-Known Member

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                        More slant info at slantsix.org
                         
                      • barbee6043

                        barbee6043 barbee 6043 FABO Gold Member

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                        I guess this type argument can be found on FBBO involving the poly 318, aka wide block poly, aka the A block, etc.....as it is called. Point is that engine can be made to have some pretty impressive numbers, (it has quite a following) , yes it costs considerable more to build, than an A,B, or RB engine, but the lovers of it, are sorta like us slant guys. Like being different, and the whole long list of why we love the slant.
                        I enjoy finding out all the characteristics of every engine or car model. The things I like, and the thing I do not. Plenty of negative and positives for each!!?????
                         
                      • Darter6

                        Darter6 Well-Known Member

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                        Yep, I had a pretty hot Poly too ! I guess I'm Slanted differently.

                        IMG_0819.jpg
                         
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