Will a Stock 489 handle 700hp?

Mopar Racers Forum

Have you had a stock 8.75, 489 hold up to 700hp while racing?

  1. Yes

    11 vote(s)
    28.2%
  2. No

    28 vote(s)
    71.8%
  1. SGBARRACUDA

    SGBARRACUDA ROY FABO Gold Member

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    Well I ran a 489 case with a spool 4.88 gears in a 8 3/4 in a 71 Scamp for 4 seasons and never broke it. Car ran 6.30’s would 60’ in the 1.35-1.40 with 4500 converter and trans brake. Ran 29.5 11.5x 15. It would hook so hard the housing dented the shocks from axle wrap. Had to use adjustable snubber to prevent that. Also had 002/003 SS springs. Guess I was just lucky eh?
     
  2. famous bob

    famous bob mopar misfit

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    It wont last if you make it hook up , but you wont with 323`s anyway ------------
    I like detroit lockers for street n strip-----------dana 60 all the way .
    When u blow an 8 3/4 every other week end , you`ll learn.
     
  3. 33IMP

    33IMP Well-Known Member

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    @70DusterBob, he built it from a truck dana, probably started with a core, for around $250, then had it narrowed, new axle ends, custom axles, and a suregrip, or spool, around 800 in parts, and a couple hundred in labor. For guys that can do their own narrowing/welding, i have heard of danas done for under a grand.
     
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    • Jadaharabi

      Jadaharabi FABO Gold Member FABO Gold Member

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      Given the choice of carrier go with the power lock not the track lock. Power lock has the clutches with two cross shafts. Trac-lok has clutches with 1 shaft
       
    • Oldmanmopar

      Oldmanmopar Going left turning right FABO Gold Member

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      I run 742 carriers 456 430' and 488's with spools and GM style yoke. Slick tire with over 700 HP All those old B-body Hemi's and Max wedges ran 742's wheels in the air from 62-66. There were no Dana's .

      I never did care for 489 carriers, They were as good as the cone style sure grips they came with from 69 -72. The only reason I would use a 489 would be to make a muscle car come with what they had. Remember most of them came with F70 14 bias tires.

      The first 8 3/4 rear I scattered was a 489. I have not broke a 742 to this day. 741's the pinions break with slicks. My first choice of a rear would be a Ford 9 inch. Three pinion bearings. one behind the yoke, One in front of the pinion gear and one behind the pinion gear. Pinion flex is the weak link that makes them break if they are not set up right. The teeth need to engage deep. I have several chunks as spares so I am staying with what I have 8 3/4, easy gear swap for 275-315 class 1/4 -1/8 mile. who can carry spare Dana's in the race trailer.

      Billet caps
      good axles
      good gear sets
      GM style yoke
      Proper pinion angle
      good stiff front segment springs

      Less reciprocating weight then the Dana.

      This is just my opinion for spending as least as possible and going racing with a 3650 lb automatic car with a 5500 stall. Same rear since the car was built many many years ago. And it will carry the wheels if wanted.
       
    • SGBARRACUDA

      SGBARRACUDA ROY FABO Gold Member

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      Actually thinking back I’m sure it was a 742 case as I usually don’t use a 489.
       
    • flyfish

      flyfish C8H18+N2O = :-D

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      For what its worth, I run a 742 3rd member in my MO875 (8 3/4) housing with 35 spline axles and a spool, foot braking at the track in my 3250lbs car and it holds up fine (runs low 10's). I also drive it all over town with my 5000 rpm converter and 4.10 gears. If built right it works just fine.

      .....BUT, if I were you (with the power that you think you might have), I would either go with a Dana, or a Ford 9 inch. I would probably lean toward the 9 inch because there is a better selection of gears.
       
    • j par

      j par Well-hung Member

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      First thing you need to do is get out of that where can I run down and buy one mind frame...
      I watched Craigslist till what I was looking for a popped up. It was a Dana 60 heavy duty out of a Dodge truck. It had 410 gears and was in excellent condition, for $160... I kept the 410 gears and sold the axles drums brakes and open carrier for a small sum of $40 to get it out of my garage and get it into the hands of someone who can use it.. now I'm $120 into an axle end gears..
      https://seattle.craigslist.org/kit/pts/d/poulsbo-dana-rear-axle/7212731488.html
      ^^^that's just a super quick two-minute search for the first thing I found but again I did a little bit more research and waited for the time to be right..
      So add to that $120 a call to Dr Dif (Cass) for $75 Mopar 8 3/4 style housing ends, a spool to put my gears on for a $125, $50 for new carrier bearings, $300 for 35-spline axles with green bearings and 3 inch studs, I think $25 for thepads for the leaf springs to weld to the rear end, $300 to have the ends and the pads welded on professionally and $175 to have the gear setup...
      Oops I lied it's $1200 and $5 LOL...
      20160123_115207.jpg IMG_20190207_083617.jpg
       
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      • j par

        j par Well-hung Member

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        And if you need backing plates you can just get them off of a Dakota truck with an 8 1/4. You can probably get the drums and all that stuff as well...
         
      • Projectile Dart

        Projectile Dart Well-Known Member

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        Kind of irrelevant but goes along the theme of what everyone has been saying... my stock rv 360 with aluminum intake and headers backed by a stockish 727 has yet to kill my 7 1/4 behind it... a rear end that has a reputation of breaking if you look at it wrong. I keep small tires on it and give it hell and it has lived for the couple thousand miles that Ive driven it (and an unknown amount of miles put on by the previous owner). Point is, on the street with no sticky tires that 8.75 should live for a LONG time, but once you start giving it big system shocks and hard launches with stickys, then you will find the weak links quickly.
        That being said, plenty of guys have made their 8.75s live long lives behind race dedicated cars once they got rid of the weak links. A buddy of mine has run a 8.75 in his front engine dragster with 2000+ horsepower for years years with no issue. The real question is if you want to put in the work and time to make the 8.75 work? Or do you just not want to ever worry about it again with a heavier D60?
         
      • justinp61

        justinp61 Well-Known Member

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        My guess is he's adding nitrous or boost. Most power adder cars don't need as much gear as N/A cars. Same deal with converters, a converter from a boosted combo will be tight in a N/A deal unless it's big inch, monster torque.

        Several years ago I was at I-57 drag strip and saw a nice 69 Dart street car with 275 radials and GT hood. Watching him make a pass it didn't 60' very well but it was flying on the big end, it ran 6.0's (1/8) at some insane mph. When I checked it out I found it had a 588" (IIRC) wedge and was pulling 3.23 gears. That explained the soft leave and huge mph.

        To the OP, call Strange and talk to them about a S60, buy once, cry once. I bought mine directly from them and other than giving them my CC number it was painless.
         
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        • j par

          j par Well-hung Member

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          Sounds pretty simple you can just call and run your credit card for 2400 for a d60 and wallah it shows up at your door or you can do some legwork and get it for about 1200...
          Probably the same scenario for an 8 and 3/4 but all you get is an 8 and 3/4...
           
        • justinp61

          justinp61 Well-Known Member

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          When I bought mine it was around $1950 delivered. I considered going the truck housing route but decided not to. I don't have or know anyone local that has the fixtures to narrow one. The S-60 housing is lighter and it has adjustable spanners on the sides that make gear changes much quicker and easier. While I was waiting on the rear end I finished the mini tubs and relocating the springs into the frame.
           
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          • j par

            j par Well-hung Member

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            How many times have you change the gears?..
             
          • justinp61

            justinp61 Well-Known Member

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            None yet. But once is enough if needed. Pick your poison, I did.
             
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            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              When we all get them, you can have mine.
               
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              • AndyF

                AndyF Well-Known Member

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                I'm upgrading to a Ford 9 inch so I'll be selling the S60 out of my Duster. If you have tubs then this might be something to think about. It is 50 inches wide from hat to hat.
                DSC_2297 (Large).JPG
                 
              • A body

                A body SLO-KID

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                You can break about anything.... but odds are way in the favor of a S60 surviving your 700hp goal. The factory put D60s behind big block stick cars. These cars paled in comparison to your H.P. goals and were on a skinny rock hard tire.

                ...and don’t cheap out on your trans either. Chuck the stock front drum for a billet piece. That way when you shuck you’re 8.75, shock your sprag, the drum won’t explode incurring even more damage in your life. :)
                 
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                • fratzog lover

                  fratzog lover Well-Known Member

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                  Oh yeah...
                   
                • rumblefish360

                  rumblefish360 So close, yet so far away FABO Gold Member

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                  Pricey.. yea, but, for me I was the “EZ Button.” My garage is jammed! 3.55’s behind a 450hp 360. It’ll live forever on the street or track. 700hp? I hope not at the hit! A rear will live longer the lighter the car is. If your car isn’t super light the torque will eat up the rear.

                  If the rates lower is at the big end, and the car is very light, I can see a season or two on the track.

                  486E72BD-6CFA-43BD-BACA-E56E9A418AF6.jpeg 3D83F8C2-EAD5-4687-BE3D-6E6C151F3D92.jpeg DDE52E53-568D-41F2-A914-5C1607F0098E.jpeg


                  Oh yea! This would be the way.
                  I hear this a lot. It’s a catch 22 on cost. Ether or....
                   
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                  • fratzog lover

                    fratzog lover Well-Known Member

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                    I'll take it!:lol:
                     
                  • 70DusterBob

                    70DusterBob Well-Known Member

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                    Thanks
                     
                  • 70DusterBob

                    70DusterBob Well-Known Member

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                    Thanks for all your replies. I am going to just put the stock 489 in for now. Then save, save, save for a Dana. I just won't go racing till I get the Dana...
                     
                  • Miszny

                    Miszny Well-Known Member

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                    I want that 1200$ Dana 60 also :)
                     
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                    • Miszny

                      Miszny Well-Known Member

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                      I know a guy running 9s in Dart with 8 3/4" foot brake car but its pushing it.
                      I have the same dillema as you and am leaning towards building Dana 60...

                      You can put billet caps on 489 but there will be some cost of machining involved.
                       
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