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What would you do?

Discussion in 'The Garage' started by BurbLover, Aug 5, 2003.

  1. BurbLover

    BurbLover 1/2 ton status

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    Okay, so I just went from a 36x12.50x16.5 to a 42x15x16.5 TSL. I was running 4:10s, but were a little sluggish. I have a D60 and 14BFF. Which gears would you run? 4:56, 4:88, 5:13, other

    (I don't know how to setup as a poll.)

    Thanks.
     
  2. Silver84k5

    Silver84k5 1/2 ton status

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    Edit i just reread that... Go with 5:13's lol for sure.. no questoin about it.
     
  3. zakk

    zakk 1/2 ton status

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    [ QUOTE ]
    Okay, so I just went from a 36x12.50x16.5 to a 42x15x16.5 TSL. I was running 4:10s, but were a little sluggish. I have a D60 and 14BFF. Which gears would you run? 4:56, 4:88, 5:13, other

    (I don't know how to setup as a poll.)

    Thanks.


    [/ QUOTE ]


    I'm sooooooooo glad i saved this:

    [ QUOTE ]
    Zakk’s Dissertation on why 5.13’s are the best choice for a 700R

    Recently, I made the switch to 5.13’s in my D60/14B combo. I run a mildly build TH350 and 39.5” TSL’s. The 4.10’s I did have were killing everything: the motor, the trans, freeway “ get up” …all of it was terrible.

    So, after typing this up a few times, I will commit this document to the annals of time, and have a friend of mine host it.

    The problem with larger tires and a 700R and larger tires, is that you can’t seem to get enough RPM’s to get the OD to properly engage.

    Dr. Watson of ORD fame has this problem with the Art Carr 700R and his 42’s. There is just not enough RPM’s to shift in OD. So what little freeway driving he does do, is all done in Drive.

    When we mix this with tires in the 35-38” range, 5.13’s are a great choice.

    Assuming a true tire dimension of 35”, a vehicle with a small block motor mated to a 700R would spin 2241 RPM’s. Running with 4.88’s would have the engine humming along at 2132 RPM’s, only saving 109 revolutions of the motor per minute. All are calculated at 65 MPH.

    Assuming a true tire size of 37”, 5.13’s would net 2120 RPM’s at 65 MPH.

    Most small block motors are comfortable running between 1800 and 2800 RPM’s. 5.13’s with the addition of OD allow this number to be on the lower end of the spectrum, while allowing for maximum acceleration and off road performance. Gearing can make a motor that is slightly lighter on power really come alive, as I have found with my mild small block 350 with approximately 285HP at the flywheel.

    In closing, unless you bought your axles with 4.88’s already installed, there is no reason that this author sees to not go with 5.13’s from your present gear ratio.

    Let the flaming begin….


    [/ QUOTE ]

    not sure what tranny you are running, but the idea is the same, especailly since you got the 42's. 5.13's are the ONLY choice, or swap in a D70 rear and run 5.86's.
     
  4. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    [ QUOTE ]
    swap in a D70 rear and run 5.86's.

    [/ QUOTE ]


    Oh yeah!
     
  5. zakk

    zakk 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    swap in a D70 rear and run 5.86's.

    [/ QUOTE ]


    Oh yeah!

    [/ QUOTE ]

    crwln73 (Ken) has those. his rig is really set up!

    SM465/Doubler/5.86's/44's and locked front and rear.
     
  6. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    I'm currently building a K5 and will also run 42's on a D70 with 5.86's - I can't wait to see how it feels!! I always thought my 5.13's and 44's in my old p/u felt good so I know this should be fantastic!!
     
  7. BurbLover

    BurbLover 1/2 ton status

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    You brought uip some key point. I did forget to include a few things:

    1 - I am running a TBI 350 which will be replaced by a TBI 402 in the next 4 months or so.

    2 - I am running a TH400/208 combo. (replaced the 700R last year)

    One of the reasons I was aiming to 4:88s is the bigger engine going in and fact that I can probably get a set of 4:88 gears reasonbly cheap. Then I'd just need to get the D60 gears & carrier.

    I think what it'll come to is what I find first. I'm looking for an open carrier on both right now. That way I can weld the rear and will have the $$ for a D60 locker some time next year.

    Thanks for everyone's input.

    /forums/images/graemlins/burb.gif
     
  8. Z3PR

    Z3PR Banned

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    Think doubler.
     
  9. BurbLover

    BurbLover 1/2 ton status

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    I have a 208. It is my understanding that a doubler is not made for a 208. I actually don't know anything about one. Thanks. Maybe I should look into this as well.
     
  10. Shawn

    Shawn 1/2 ton status Premium Member Author

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    [ QUOTE ]
    You brought uip some key point. I did forget to include a few things:

    1 - I am running a TBI 350 which will be replaced by a TBI 402 in the next 4 months or so.

    2 - I am running a TH400/208 combo. (replaced the 700R last year)

    One of the reasons I was aiming to 4:88s is the bigger engine going in and fact that I can probably get a set of 4:88 gears reasonbly cheap. Then I'd just need to get the D60 gears & carrier.

    I think what it'll come to is what I find first. I'm looking for an open carrier on both right now. That way I can weld the rear and will have the $$ for a D60 locker some time next year.

    Thanks for everyone's input.

    /forums/images/graemlins/burb.gif

    [/ QUOTE ]

    I have 4.88's and they work great around town and on the trail but it gets old for driving on the highway. Going to Moab is brutal when your engine has to spin that fast and your exhaust makes you go deaf. Your turbo 400 will only be worse since the converter will take another 200rpm. If I were to do it over, and keept the 465, I would of stayed with 4.10 and let the big block do all the low rpm torque work. I'm not going back so I'm doing the 4l80. If you plan on keeping the 400, and going with 4.88 gears, just make sure you won't mind the RPM you'll be at going down I-25 at 75mph.
     

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