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who's got 4.56's,35's and a 700r4

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by efilnikufecin, Jul 24, 2002.

  1. efilnikufecin

    efilnikufecin 1/2 ton status

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    who\'s got 4.56\'s,35\'s and a 700r4

    just wondering what kind of rpm's you run at about 75 or 80mph.getting 4.56's installed this week and was just wondering.thanks
     
  2. UseYourBlinker

    UseYourBlinker 1 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    Scott (4X4HIGH) does..send him a PM,or just wait till later tonight when he replies /forums/images/icons/grin.gif
     
  3. TXsizeK5

    TXsizeK5 1/2 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    Hrm, I'd like to know too /forums/images/icons/tongue.gif
     
  4. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    I run a 350/700 Raptor/4.56s and 35s. Works for me. At 80 mph the RPMs are indeed "up there". I dont have a tach, and couldnt even begin to guestimate what the RPMs are at, but the engine is definitely working. I never go over 75mph... and rarely ever even go that fast, so I dont worry about it.

    J
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    4lo.com has a calculator.

    With true 35" tires, 4.56 gears, and the overdrive of a 700R4 with the torque converter locked:

    75 mph - 2298 RPM
    80 mph - 2451 RPM

    Hey non-OD guys, don't you wish your RPM looked like this?

    (just for reference, my 1 ton turns 3400-3600 RPM at 75-80 MPH!!)
     
  6. Zeus33rd

    Zeus33rd Smarter than you GMOTM Winner

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    I do about 3100-3200 rpm's at 75mph. I'd love to swap to a 700 one day. Lower 1st gear and that awesome OD. /forums/images/icons/grin.gif
     
  7. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    I have 4.56's, tires that measure 33.75" diameter (most 35's are not true 35's), and a 700 with lockup. At ~75MPH I turn ~2600 without the converter locked and ~2400 with it locked.
     
  8. TXsizeK5

    TXsizeK5 1/2 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    Can I ask a stupid question? What exactly do you mean by locked up and not. I know you can buy trannies with either lokcup or nonlockup but whate exactly does that mean? Thanks
     
  9. kpanza

    kpanza 1/2 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    I've got that setup right now...I'd say that it's in the 2600 rpm range at 75 and a tad higher at 80 mph...definitely a large increase from my old 3.73s! Man, I used to be turning like 1800 rpm at 60 and maybe 2200 at 75 with those things - it was TOO low to be in the powerband!

    As soon as I get my hydraulic ram steering setup on the truck I'll have to give her a test to see what the real rpms are at speed...
     
  10. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    As you know some transmissions have a lockup converter. The 700r4 is one of those transmissions. By nature an automatic transmission is a fluid pump with a hydraulic coupler (a.k.a. torque converter). By design there is some slip built in due to the fluid so when in drive the transmission should turn the same RPM as the motor (such as with a 1:1 manual transmission gear), but the slip in the converter causes the transmission to turn slower and the energy is lost as heat (not good for auto trannies), with a lockup converter, there is an internal clutch (hydraulically actuated) that couples the input shaft of the tranny to the shell of the converter (which is bolted to the flywheel), causing the input shaft to turn the same RPM as the motor, this reduces heat since the converter is not "slipping" and transfers more energy to the rear wheels (more efficient) and therefor at a given speed lowers your engine rpms vs. when the converter is unlocked. Less wear and tear on the tranny and motor.
     
  11. Blazinaire

    Blazinaire 1/2 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    I have 35''s, 700R4, and 4.56's /forums/images/icons/laugh.gif . Too bad I don't have a tach! /forums/images/icons/crazy.gif , but I will say that right around 75 mph is the maximum that I would maintain for any amount of time. If I wanted to go fast, I would have bought a car /forums/images/icons/wink.gif
     
  12. efilnikufecin

    efilnikufecin 1/2 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    thanks everyone.my 3.73 just didn't cut it.i was afraid of burning the tranny up so i'm stepping up to 4.56's.the converter would only lock up going down hill.i know without it being locked they like to heat up and 700's don't take kindly to heat.thanks again.
     
  13. Blue85

    Blue85 Troll Premium Member

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    Just for another data point, I have 700, 35's (probably shy of 34" in reality) and 4.10 gears, which puts me at about 2200 @ 75rpm. 4.10 works well, but 4.56 may be even better. My truck shure scooted with 4.10 and 33"
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    I had 4.10s and 35s with my 700 and I wasn't happy at all.
     
  15. Blue85

    Blue85 Troll Premium Member

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    Was that with a 305?
     
  16. BLUESMAN

    BLUESMAN 1/2 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    PM "C'MOE" cause he has a TH350 with 4.56's and 35" tires.I know he really wants an TH700 trans.....the RPM's are killing him.
     
  17. Living Large

    Living Large Registered Member

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    My 1986 GMC with BFG 35 MT, 700R, and 4.56 gears runs 2260 at a corrected speed of 75 mph. Puts the engine right in the torque curve with the combo. This is with a modified trans with the computer controlled lock up removed. The torque coverter is always locked up, which helps to reduce heat and rpm's. It was the best mod that I have done as compaired to the stock 3.08 gears.
     
  18. topless1tonk5

    topless1tonk5 Registered Member

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    i ran that combo for a long time with my 1/2 ton set up, it worked pretty well but i live in the mountains and prefer to drive 80+ mph and i wish i had 4.88's. there is nothing wrong with taching 2700 when your covering groud like that, trust me, gearing aint cheap, go as deep as you thing you will ever need the first time, you can always buy bigger tires! /forums/images/icons/grin.gif
     
  19. Diesel Dan

    Diesel Dan 1/2 ton status

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    I noticed the same thing crossing the mountains in PA when I brought home my sub. Not alot of climbing power in OD at 65-70.
     
  20. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: who\'s got 4.56\'s,35\'s and a 700r4

    Well my speedo is off. When I'm turning 2800-2900 RPMs I'm still getting passed with TH350, 4.10's a BFG KO 35's. Course they drive like idiots here. In my Supra with the cruise on 80 mph I'm only passing half the cars on the road. the other half is passing me doing 85-90. Hehehe They don't call 285 (loop around Atlanta) the Atlanta Autobahn for nothing. OD would be nice. That's why I went 4.10 cause of the speed they run around here. Had to be able to go fast enough not to get run over. Really felt like I lost a ton of power when I went from 32's- 35's /forums/images/icons/smile.gif After riding on the hwy in BigJbears truck and listening to the engine wound out and getting passed by 72 beetles and he even has lock up converter I knew 4.56 was going to be a little high for my tastes. Now if I had a 700R4...4.56 all the way. It's just right.
     

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