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. forphorty

    forphorty Well-Known Member

    Messages:
    739
    Likes Received:
    335
    Joined:
    Jan 19, 2006
    Local Time:
    12:15 PM
    IMO, forget about the sturdiest rear end, drag strip performance or a chassis dyno. Get it on an engine dyno first and perform proper tests with as few variables as humanly possible. If this device is as revolutionary as you say, you should sell everything you own if needed to get its capabilities verified.
     
    • Like Like x 1
    • oldkimmer

      oldkimmer FABO Gold Member FABO Gold Member

      Messages:
      18,847
      Likes Received:
      6199
      Joined:
      Nov 11, 2006
      Location:
      Kindersley, Saskatchewan,
      Local Time:
      12:15 PM
      So it’s a torque multiplier. Kim
       
    • oldkimmer

      oldkimmer FABO Gold Member FABO Gold Member

      Messages:
      18,847
      Likes Received:
      6199
      Joined:
      Nov 11, 2006
      Location:
      Kindersley, Saskatchewan,
      Local Time:
      12:15 PM
      Sounds like u were willing to take a big chance on an 8 3/4. U shouldn’t of even considered it. Kim
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      "Maybe 800" IDK, I am trying my best to get it on a chassi dyno to find out.
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      Thanks
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      It has to do with airflow. The design I tested before worked better at low end than top. I'm hoping this one works better throughout the power band...
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      It increases the power of the explosion in the combustion chamber, so it increases torque, hp is a by product.
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      The "mechanic" as he calls himself, told me an 8-3/4 with a 742 could handle it if I'm not popping wheelies. From what you guys are saying I need a Dana. But I have a good strong race 489 in it now, the housing has a brace, my car weighs 2900 lbs empty, or so it says on the title, but that was with a /6. I have a 360 block in in now, and a 727 as opposed to the 904 it came with, so with me and mentioned mods maybe 3300. I do not plan on popping wheelies, just a smooth take off consistently should provide an et difference that would be impressive enough for an investor to find it interesting. I know a pro drag racer and may have to pay him to get the consistency on the peddle I need.

      I don't plan on racing it in competition.
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      I'm trying.
       
    • flyfish

      flyfish C8H18+N2O = :-D

      Messages:
      2,247
      Likes Received:
      830
      Joined:
      Apr 16, 2007
      Location:
      Indy
      Local Time:
      1:15 PM
      If you are not launching it hard you might be fine with the 8 3/4....just know that sticky tires and a hard launch could break it.

      Might as well mention this too, my 8 3/4 has held up fine over the years. It has survived years of nitrous launches (~9 years) and the more recent (the last 11 years) is has survived stroker motors beating on it almost every weekend in the 10's. This is on a 3250# footbrake car. I know that I'm on borrowed time, but just know they can survive.
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      Thanks, I plan on doing some chassis dyno testing with it. I think it will be fine. I do have drag radials on it, couldn't find 50 series in a street tire. I just have to be careful until I get a Dana under it.
       
    • Walker434

      Walker434 Well-Known Member

      Messages:
      955
      Likes Received:
      663
      Joined:
      Aug 29, 2012
      Location:
      Nashville, TN
      Local Time:
      12:15 PM
      My 8 3/4 stock rear was making some awful noises when I was running High 11s in the quarter, probably bearings going out. Rather than spend more money on the 8 3/4 I built a junkyard Dana 60 because I had plans to make more power.

      My car has recently gone a best of 6.27 in the 1/8th mile with the Dana 60. This is with Dr. Diff's truetrack and stock truck 3.54 gears. I do however run 35 spline moser axles.

      Mine is also a street/strip car. I would just spend the money on the Dana and forget it. You will get addicted to going to the track and if it's a street car you don't always want to trailer it because you are worried about blowing up your 8 3/4.
       
    • 70DusterBob

      70DusterBob Well-Known Member

      Messages:
      713
      Likes Received:
      167
      Joined:
      Feb 20, 2016
      Location:
      Texas
      Local Time:
      12:15 PM
      Thanks for the reply Walker,

      Yeah, I agree, I would rather have overkill and not have to worry than under and have to baby it afraid to really get on it. Good point there...
       
    1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
      By continuing to use this site, you are consenting to our use of cookies.