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454 and 39.5's...DD?

Discussion in 'The Garage' started by GRAYTEXK5, Jun 18, 2004.

  1. GRAYTEXK5

    GRAYTEXK5 1/2 ton status

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    454 and 39.5\'s...DD?

    how many of you have big blocks and/or 39.5 or larger tires on your daily drivers? right now, mine has a 350 with a few basic mods, and 36" SX's. it's not my DD, but it used to be, and may be again soon. I know it's gonna get terrible mileage no matter what, it already does, but will it really be all that much worse with the 454? it'll have 4.10 gears, for now, but will the extra power of the big block somewhat make up for that? and how bad will it ride with 39.5 TSL's? I'd like to hear what you other guys with similar setups think of them...how you like, or don't like it? thanks for your help. /forums/images/graemlins/thumb.gif
     
  2. or2play

    or2play 1/2 ton status

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    Re: 454 and 39.5\'s...DD?

    I have 42s on my suburban. I drive it to work everyday. I try to avoid driving it unless I have to (unless I'm taking it to go play.) For TSL's that aren't the roundest tire in the world I guess I can't really complain about the ride. And they get flat spots like its cool. But hey what do you expect from bias tires. /forums/images/graemlins/dunno.gif
     
  3. NITRO

    NITRO 1/2 ton status

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    Re: 454 and 39.5\'s...DD?

    I have a 454 with 500 hp and MT 39.5/18/16.5's and I used that truck for my DD for quite a while. I get about 4 mpg. I have 5.13's and a th400. I dont think you are going to do too good with 4.10's anywhere with having tires that big on it. Even with the bigger engine, it is going to be hating life. I would say wait until you have the money to regear it so you can get the whole setup working together.

    NITRO
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: 454 and 39.5\'s...DD?

    I can DD my truck, but with the big swampers it's nowhere near as much fun to drive as when it had 35s.
     
  5. ratzila

    ratzila 1/2 ton status

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    Re: 454 and 39.5\'s...DD?

    I have a suburban with a 454 that used to run 39.5 tsl. It was my dd until I bought a toyota pickup. My gas mileage in the burb went from 6mpg with the 39.5 to 8mpg with the 44 boggers. This is with 5.13 gears. At least now the gas prices are dropping a little bit. /forums/images/graemlins/woot.gif
     
  6. RingMaster4x4

    RingMaster4x4 1/2 ton status Premium Member

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    Re: 454 and 39.5\'s...DD?

    I drove mine as a DD for about 2 year and I did not have anyproblems. I get around 10 MPG. With a 427 44" groundhawgs (really only a 41") and 4.56 gears.
     
  7. willyswanter

    willyswanter 1/2 ton status GMOTM Winner

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    Re: 454 and 39.5\'s...DD?

    Vortec 454 with 39.5's and 5.13's I get 14 on the highway and 9-10 in town.
     
  8. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Re: 454 and 39.5\'s...DD?

    I have an injected 350/th350/4.56's and i was running 38" TSLs for a while and switched back to my old 35" mud's for street use.
    I drive my truck everyday. It gets 13mpg on the freeway and probably about 8 around town... After i swapped in the 1 tons and 38's i could literally see the tires wear after only a 100 mile trip or so. Grooving them probably made them wear out a little quicker also.. Swampers just suck for the street but are ideal for offroad.. I finally realized i'm not going wheeling everyday so i'll keep my 38's in the shed so they still have tread when i want to go wheeling.. Buy some cheapy rims for my 35" muds and run those till they're bald as my street tires. /forums/images/graemlins/waytogo.gif Gas is one thing... if i put a BBC in my truck with the way i drive, i wouldn't be able to afford to drive it everyday. If you can afford the gas, go for it.. The tires are another issue.. Run those bias 39.5's but you'll be sad after a few months. /forums/images/graemlins/ignore.gif
     
  9. k20

    k20 3/4 ton status

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    Re: 454 and 39.5\'s...DD?

    i aint got the big tires, but 496 that gets 10 in city/12highway, premium only though /forums/images/graemlins/doah.gif
     
  10. GRAYTEXK5

    GRAYTEXK5 1/2 ton status

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    Re: 454 and 39.5\'s...DD?

    thanks for the input guys. I may just hold off on the 39.5's for now...or try to find a way to regear at the same time. but when I do get new gears...what ratio would be best for this combo, with a th400 tranny? would 4.56's be enough, or should I go ahead and get 4.88's, or even 5.13's?
     
  11. HarryH3

    HarryH3 1 ton status Author

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    Re: 454 and 39.5\'s...DD?

    5.13's and 39.5's would put your highway RPM almost exactly where it would be with 3.73's and the stock 29 inchers. /forums/images/graemlins/thumb.gif
     
  12. GRAYTEXK5

    GRAYTEXK5 1/2 ton status

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    Re: 454 and 39.5\'s...DD?

    [ QUOTE ]
    5.13's and 39.5's would put your highway RPM almost exactly where it would be with 3.73's and the stock 29 inchers. /forums/images/graemlins/thumb.gif

    [/ QUOTE ]

    well, I never had it with stock tires. when I got it, it had 35's and 3.40's! /forums/images/graemlins/yikes.gif and now it has 36's and 4.10's. but what you said sounds good to me. thanks. /forums/images/graemlins/peace.gif
     
  13. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    Re: 454 and 39.5\'s...DD?

    [ QUOTE ]
    Vortec 454 with 39.5's and 5.13's I get 14 on the highway and 9-10 in town.

    [/ QUOTE ]
    Jerk. /forums/images/graemlins/smile.gif



    39.5's + 4.10's + th400/454 = terrible mileage, no power, and probably a burnt up auto eventually. I agree that 5.13's would be the best. /forums/images/graemlins/thinking.gif
     
  14. zakk

    zakk 1/2 ton status

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    Re: 454 and 39.5\'s...DD?

    5.13's
     
  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: 454 and 39.5\'s...DD?

    [ QUOTE ]
    39.5's + 4.10's + th400/454 = terrible mileage, no power, and probably a burnt up auto eventually. I agree that 5.13's would be the best. /forums/images/graemlins/thinking.gif

    [/ QUOTE ]

    I disagree. I run 38.5s and 4.10s and I'm turning 2400 or so RPM at speed. Add an inch of tire height and your cruise RPM is still 2000-2200, which is far more than any truck with overdrive from the factory.

    4.10s and 39.5s isn't exactly ideal, but it'll be far from the way you describe it.

    Try driving your truck in drive sometime instead of overdrive and tell me that at highway speed it doesn't seem over-geared.
     

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