Trying to get Power out of a 225

Discussion in 'Slant 6 Engines' started by Shane Clark, Jan 6, 2017.

Discuss Trying to get Power out of a 225 in the Slant 6 Engines area at forabodiesonly.com.

  1. Shane Clark

    Shane Clark Member

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    hello, I'm building a slant six and so far have the head getting ported polished, new valves, etc. I also have a cam with 264/264 duration .440/.440 lift. I'm also most likely gonna get the crank balanced and see what I can do with lightening the bottom end up. any tips on what else i should do? looking for a good street/strip engine nothing to crazy. 300hp area would be nice. thanks!

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    • 273

      273 Well-Known Member

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      300 is about an all out /6.
      What you doing for compression?
       
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      • Shane Clark

        Shane Clark Member

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        yeah i know 300 is kind of a lot. my machinist said he will mill it down enough so i wont have to get new push rods so probably around 9:1 to 10:1. if i get like low 200s ill be happy just aiming high haha
         
      • jimjimjimmy

        jimjimjimmy lobsterman FABO Gold Member

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        about 13lbs of boost should do it .
         
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        • Shane Clark

          Shane Clark Member

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          lol maybe in the future ill think about a turbo. too much money for my budget at the moment haha.
           
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          • 65 Dartman

            65 Dartman FABO Gold Member FABO Gold Member

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            I expect to have about a shade over 200HP out of my slant. The block has been bored 30 over, decked 90 thou head cut 10 thou, 1.70/1.44 oversize valves 340 valvesprings installed, mild port and polish on the head, pretty stout cam. All the measurements indicate close to a 10 to1 CR and about a 8.05 Dynamic CR. Will be running Clifford long tube headers and an Offy 4 barrel intake with a FiTech unit. It ought to go pretty good in my early A wagon with a 4 speed and 3.23 gears.
             
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            • Shane Clark

              Shane Clark Member

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              okay that pretty good because thats what im hoping to get. so how much is a FiTech and is it worth it? arent those like a grand? and thats gotta be cool with a 4 speed haha. i just bought a reverse manual valve body for my 904.
               
            • mopar_nocar

              mopar_nocar Well-Known Member

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              Last slant that I built was in a 65 barracuda. It turned in a best e.t. of 14.7s. I do not have the time slips, so I do not recall the weight of the car. However, it should have been a 180-190hp slant.

              Basics of the build:

              .030 over
              1.77/1.44 valves, basic resurfacing of head
              .100 off the block
              Factory super six intake w/adapter for a 350cfm holley 2bbl
              Cheap chinese crap exhaust manifold attached to 2.25 full exhaust
              do no recall the cam specifics, but it idled smooth as silk
              904 stock transmission
              4.10 rear when it ran the 14.7, mid 15s with 3.55s

              Drove it all over San Antonio when it had the 3.55s. Lots of fun on the road. People always thought it was V8. I never told otherwise. Really wish I still had the car. I, no doubt, left a lot on the table power-wise, but it was a great daily driver.

              You really need to check out slantsix.org if you haven't found it yet.

              sb
               
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              • Shane Clark

                Shane Clark Member

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                14.7 is pretty darn good for 190hp lol. im hoping for just a little over that. i need to get an 8 3/4 and im thinking 3.91 or 3.73 somewhere in between streetable and drag
                 
              • 273

                273 Well-Known Member

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                Head is the biggest limit on power. Stock I believe would be lucky to make over 180-200 hp. So depending on your head work you might get to 1hp per cid.

                Besides head gearing is /6 biggest weakness and biggest improvement . To take it to extreme example to show the up hill battle of the /6. If you had a 440 (basically double the /6 size) with 2.74 gear and your /6 hp level. You would need twice the gear of 440 to keep up (5.36 ish) not saying to go with that much gear but to me anything under 340 should have at least 3.91 if you want performance. Also could go with 80's tranny for deeper 1st and 2nd not the best solution but at least make light to light more fun.
                 
                Last edited: Jan 6, 2017
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                • Darter6

                  Darter6 Well-Known Member

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                  I've Drag raced Slant Six cars for years.First MAJOR question,,What is your BUDGET ?
                   
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                  • Shane Clark

                    Shane Clark Member

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                    im getting the head done over so i think that will help and okay ill definitely get 3.91s then
                     
                  • Killer6

                    Killer6 Well-Known Member

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                    There's a big difference between 9 & 10:1 squeeze, you'd better know which one, by the sounds of it you're talking 9:1 if the milling is all you're doin' and keepin' the pushrods.
                    Welcome to FABO! The head is definitely the main power factor to get right, the more flow You can get out of it the happier things will go for You, :thumbsup:
                     
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                    • Shane Clark

                      Shane Clark Member

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                      id say around 4000 maybe a bit more if needed and i already have 1300 into it
                       
                    • Shane Clark

                      Shane Clark Member

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                      thanks! ill talk to my machinist about it more in depth soon.
                       
                    • Darter6

                      Darter6 Well-Known Member

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                      With 4K you can do allot to a slant. A well known Nebraska racer shared a plan that I call the 3-100's.Mill .100 from the head,.100 from the block and bore it .100.That is your starting point. To get less rotating mass you may want to find a block with a cast crank as they are much lighter. A 1980 slant will have the cast crank and will handle 300+ HP no problem.Even though I always used the drool tube head (spark plug tubes) It is said that the later peanut plug head can be worked a bit more for more power. Stock Slant pistons look like beer cans attached to the rod.Modern pistons are the way to go and much lighter.Lots of guys are using the K-1 rods to gain even more.

                      Now using what you have you can pull 200 HP at the crank.A basic stock head milled .100, stock bottom end ,good cam,valve springs,4 bbl intake 500-600 cfm carb and headers and 4.30 geared car pulled 208 HP at the crank and close to 180 at the rear wheels on a chassis dyno.This was in a street 2600 lbs 67 Dart and ran a best of 15.47 in Tulsa almost 20 years ago.

                      Everything I ever did was N/A. Slants do amazing things with a turbocharger and perform well on the street.At one time the Supercharger Store mad a kit for the Slant.Again making serious streetable power.

                      There will be pros and cons as everybody does things different but for sure it is allot of fun.I've been out of the game now for a few years and sure miss it. As it's said "Dare to be Different"
                       
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                      • whitepunkonnitro

                        whitepunkonnitro FABO Gold Member FABO Gold Member

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                        Do everything you can to build bottom end torque, and get ready to feed it a very serious torque converter.
                        If I had to identify any specific Slant weakness, its a lack of bottom end torque, which is a product of its unorthodox geometery. Too long a rod, too small a bore.
                        From 3000 up, they can really turn on. Out of the hole they are absolutely miserable.
                        The ironic thing, is that nearly all of the popular mods, bigger valves, cam, etc, only make it worse down low.
                         
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                        • AJ/FormS

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

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                          And that hole is immediately noticeable the very second you put it in gear with even a tiny bit bigger cam, and the stock TC.
                          Nitro nailed it;Big TC and Big gears.
                          Also; fresh cold air, headers and a free-flowing exhaust. These are non-negotiables.
                          So forget hi-way cruising forever.
                           
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                          • Darter6

                            Darter6 Well-Known Member

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                            ^^^^^^^^I agree the proper torque converter is a must.The modified slants that I had came alive in the 3000-3200 range.My last street slant we made fun of it with a 2200 rpm converter.It would leave the line like a super gas car crawling out of the hole then coming alive 60+ feet out (with 2.94 gears) A 8'' 5000 rpm converter and 4 .10 gears sure made a difference..
                             
                          • Shane Clark

                            Shane Clark Member

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                            okay so i need to
                            -lighten up bottom end
                            -mill block,head, and bore it
                            -get a good torque converter
                            -get shorter gears
                            okay those all sound pretty reasonable, thanks for the help!
                             
                          • Darter6

                            Darter6 Well-Known Member

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                            Good luck and please keep us updated on the progress.Pictures too !
                            Any questions,,We are here to help.
                             
                          • Killer6

                            Killer6 Well-Known Member

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                            Keep in mind when You pick a torque converter they are advertised w/an "avg" stall range, read smallblock V8, so say a 350/360 inputs 50% more Tq than the little /6.
                            You've got to pick around 1K above to get what you want, more if the cam is real big..........so think 4200 rating & up.
                             
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                            • diymirage

                              diymirage HP@idle > hondaHP@redline FABO Gold Member

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                              at this point i wouldnt "pick" a torque converter at all
                              i would call one of the reputable torque converter builders and tell them what you have, what you want and have them build you one

                              when i did my duster i called three different companies, all of which came highly recommended on fabo, and went with the one that asked the most questions...which happened to be PTC

                              that ended up costing me about $500 including shipping and it handles like a dream
                              the car idles in gear at 700 and will creep if i let my foot of the brake, but if i get on the go pedal the engine will jump to 3200 ish before the converter engages, the tires start to fry and the rear end starts coming around
                               
                            • Backtobasics

                              Backtobasics Well-Known Member

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                              slant six | PowerNation Search

                              Above is 2 part video series on a .040 slant six rebuild with a 440 lift cam, head rebuilt, but no significant head mods, Hooker headers, 4 barrel Offenhauser intake with 500cfm Edelbrock carb. 2.5 Magnaflow exhaust. Trans = 904 rebuilt, but no data on stall converter. 3.21 gear set. Tuned to 132 HP / 170 TQ at the wheels.
                               
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                              • roccodart440

                                roccodart440 Well-Known Member

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