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Gear ratios

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MudbogAD, Jun 29, 2001.

  1. MudbogAD

    MudbogAD 1/2 ton status

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    I have a 79 Jimmy with 3.08 and 35's. Would I notice a significant performace increase if I upgraded to 4.56's.
     
  2. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    Ummm yeah! Although you might wanna consider 4.10's which would be easier on the gas mileage if you are using this truck as a daily driver....but if you are a rock crawler and don't pavement pound 4.56's would rock!

    I removed my quote so gay, vegetarian, minority, eco-nazis who love Jesus, nuke spotted owls, vote Gore and smoke medical marijuana won't be offend.
     
  3. MudbogAD

    MudbogAD 1/2 ton status

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    thank you
     
  4. Sammy

    Sammy 1/2 ton status

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    Hold up. Few months back I asked about the same question. I do not rockcrawl, but I do offroad trails that are not for the faint at heart. Everybody told me to go 4.56. And now it is 4.10?



    "1988 K5 Grand GT Blazer Silverado in the Netherlands."
     
  5. 90blzr

    90blzr 1/2 ton status

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    She was just giving him something to look at and to think about. Like she said he WILL notice a performance increase with either one of those choices. No one is saying that you shouldn't go with the 4.56. It all depends on what you use the truck for and what rpms you are comfortable running at, wether or not you have overdrive and wether you care more about mileage or performance of the lower gears. Lots of things to take into consideration. She was simply pointing out his options.

    <P ID="edit"><FONT SIZE=-1>Edited by 90blzr on 06/29/01 01:42 AM (server time).</FONT></P>
     
  6. Sammy

    Sammy 1/2 ton status

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    So with 700R4 208 35"X14.5" tires. And a need to pull CJ's and TJ's and XJ's out of trouble. Is it still 4.56?



    "1988 K5 Grand GT Blazer Silverado in the Netherlands."
     
  7. 90blzr

    90blzr 1/2 ton status

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    Just to give you an idea. I have a 700R4 w/241 and 33x14.50 tires and I have 4.10's. It does fine in OD. I am at about 2100 or so doing 70. The 1st,2nd and 3rd gears are good for around town also. I think that with 33's and OD 4.10's are perfect. With your 35's and wanting to pull out the stuck heeps, and the hard wheelin you do, I would say that the 4.56 would be much better for YOUR needs than the 4.10's. This is just my opinion. If you want to check what your rpm's would be at different speeds you can go to www.4lo.com and use the calculators to give you a better idea of what you will be looking at.

    <P ID="edit"><FONT SIZE=-1>Edited by 90blzr on 06/29/01 01:56 AM (server time).</FONT></P>
     
  8. CaptCrunch

    CaptCrunch 1/2 ton status

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    I agree with ya 100% 90blzr,,, I have 4.10's now and for a hardcore rig w/ OD I'd recomend it. I like the 4.10's I have... excellent off the line and still gets as good of gas milage on the freeway going 70 as my 3.08's did. They fit well for my daily driver... for someone with a rig that only sees trails and occasional on the street driving go 4.56's no matter what tranny. As soon as I step up to 3/4 ton's and my rig moves to a secondary driver status I'll go 4.56's or maybe even 4.88's since I plan to step up to 38's

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <A target="_blank" HREF=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</A>
     
  9. 6.2Blazer

    6.2Blazer 1/2 ton status

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    Yes, going from 3.08 to 4.56 gears will give a noticable improvement in acceleration.

    Concerning the debate between 4.10 and 4.56 gears, a lot depends on what transmission you are running. I'm assuminy your '79 has a stock transmission which means no overdrive. 4.56 gears with 35" tires might not be optimum when it comes to freeway cruising and gas mileage, though it shouldn't be that bad (again in my opinion). The newer Blazers with overdrive can get by with much lower gears and still have good engine speed on the highway. A 700r4, for example, has an overdrive gear of around 0.70:1. This means in overdrive on the freeway 4.56 gears would be equivalent to about 3.20 gears (4.56 x .7 = 3.19) in a vehicle without an overdrive trans.
     
  10. BigTex

    BigTex 1/2 ton status

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    Mine is a daily driver but I'm going with 4.56s. I love to feel the power on command!!!

    <A target="_blank" HREF=http://www.thehungeronline.com>http://www.thehungeronline.com</A>
     
  11. FRIZZLEFRY

    FRIZZLEFRY 1/2 ton status

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    If I had a 700 I would have gone with 4.56s but Ive got a th350 so I did 4.10s.

    <A target="_blank" HREF=http://community.webshots.com/user/beaterwhang>http://community.webshots.com/user/beaterwhang</A>
     
  12. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I've got a 700R4, 35s, and 4.10s. If given the choice I think I'd have 4.56s, but my truck has no problem pulling itself down the highway and I can accellerate in overdrive no problem. 4.56s would just be a little more fun. I can get my truck sideways no problem and if I want to I can smoke off my BFGs. I don't though, too expensive!

    Don't laugh, I've got a built 305. I know I'm dumb for building up a 305, but it's all I had. It was supposed to be a 350. I got screwed over on that deal, so did the PO who was sold the motor for $1000. I paid $100 for it and it's got a LOT of power. You'd be amazed. But it's still a 305, which bothers me.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  13. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    I have the 700R4 and run 33's with 4.56's My gas mileage around town is a little better then with the 3.08's. I'm not hitting the skinny pedal as hard to get up to speed. I am tacking around 2200 at 65. It is not my daily driver. But most of the driving is around town. If I had to do my gears again I would go with the 4.88's. 4.56's are not as bad as everybody thinks........Just my .02 worth
     
  14. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I think 4.56s would be nice to have, but 4.10s are good too. Even 5.13s wouldn't be that bad with 35s, 2500 rpm at 65 mph. All depends on how snappy you want it, and if you plan on bigger tires, go lower.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  15. MudbogAD

    MudbogAD 1/2 ton status

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    I think i will go with the 4.56's because i am not too concerned with mileage and rpm. I want performance! Thanks all !!!!!
     
  16. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    youll be using the truck as a daily driver, i know you will, 4.56s would be nice if you go up to 36" and inflate them all the way so they're actually 36" tall unlike your 35s witch measure out at about 33" due to the pressure you run. that truck sucks on mileage already what are you gonna drive if your mileage gets worse? the van? i dont think so. that truck has got PLENTY of power so 4.11s would be ok for you. certain companies make 4.33s too, think about those. i think if i were you i'd go with 4.33s.
     
  17. BLzr4x4ngkid

    BLzr4x4ngkid 1/2 ton status

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    Hell just drop some 5.13's in it! Actually, with OD, I'd go with 4.56. If you had a TH350 or 400, then 4.10 would work. I have 38's on my Blazer with a TH350 and I'm prolly going with 4.88 or 5.13. I'm also going to drop my 3/4 ton drive train in too. Mine's a daily driver with expired tags too!

    Pedal mashed and KICK'N ASS!
    WFO! Wide [censored]'n OPEN!
     
  18. MudbogAD

    MudbogAD 1/2 ton status

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    scott/muddsub. You have 29 inch tires and 3.73's. You probaby get worse mileage than the jimmy would with 4.88's. My Jimmy never drives on the highway or freeway so I think 4.56's will do fine. Especially if I am going with the 36x12.50 very soon.
     
  19. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    hey adam they're 30s ok and i wont have them for long

    scott,
    1989 suburban 3/4t 4" lift soon to be rollin on 35s, tbi350
     
  20. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    Go with the 4.56. It is not a car, it is a truck. Trucks have low gears. Now, so you don't think I'm a nut, the reasons. My '80 has no power from the motor: stock 350, 21years & 200,000 mi. When I replaced the flexplate I could turn the motor by hand, plugs in, w/o gloves. Before the gear swap it would not start good, slow down good, and would not crawl at all. With the 4.56s it is like a new truck. The gas mi sucked before and it still does now. Once again, it's a truck. This was my daily driver untill I started my new job with a 90 mi/day commute. The first month I drove it to work in Atl traffic. It still keeps up fine untill about 70MPH. If you have a good motor you'll be even better. The guys with the 4.10s wonder about 4.56s. The guys w/4.56s wonder about 4.88s. With 35s & no O/D 4.56s are perfect. 35s & O/D, go with 4.88s. One thing to remember, only BFGs and Swampers are true hight.

    Jim '80 GMC
    Freedom First!
    <A target="_blank" HREF=http://www.bigjbear.coloradok5.com>http://www.bigjbear.coloradok5.com</A>
     

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