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Author Topic: top speed of 79mph? wth? rear end gears?  (Read 7552 times)

Offline 84scottsdale454

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top speed of 79mph? wth? rear end gears?
« on: May 28, 2011, 10:47:43 am »
i have a stock 454 installed with a turbo350 trans, i cant look at my gears at this time......can someone give me an idea on what they will be? i think this rear end was custom built before i bought it! any ideas?????????
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Offline Psycho71

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Re: top speed of 79mph? wth? rear end gears?
« Reply #1 on: May 28, 2011, 11:20:52 am »
what kind of rpm are you turning at 79mph, or 60mph, or whatever? Tire size will ploy a role in that as well. With both of those figures, and the 1:1 thrid gear of the th350, it's just math to get the rear end ratio.
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Offline 84scottsdale454

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Re: top speed of 79mph? wth? rear end gears?
« Reply #2 on: May 28, 2011, 11:29:33 am »
unsure of the rpm, it was the max rpm because thats all it could take....i could not go 80mph! the tires size are the stock height
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Offline VileZambonie

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Re: top speed of 79mph? wth? rear end gears?
« Reply #3 on: May 28, 2011, 02:38:20 pm »
You have given nowhere near enough information for anyone to even venture a guess and at that all you will be getting are random guesses.
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Offline malibu795

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Re: top speed of 79mph? wth? rear end gears?
« Reply #4 on: May 28, 2011, 10:30:53 pm »
Quote from: VileZambonie on May 28, 2011, 02:38:20 pm
You have given nowhere near enough information for anyone to even venture a guess and at that all you will be getting are random guesses.
yep
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adam wildman
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Offline slammed79

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Re: top speed of 79mph? wth? rear end gears?
« Reply #5 on: May 28, 2011, 10:34:50 pm »
Shove a $30 dollar tach in there and get a rpm reading. Then please report back with rpms and the actual tire size. Stock doesn't help in the slightest.
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Offline 84scottsdale454

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Re: top speed of 79mph? wth? rear end gears?
« Reply #6 on: May 28, 2011, 10:50:57 pm »
your a smart man slammed79..... imma get a tach, me and the ol man pulled it out today, they were 4.56s! well thats what he says anyway! i appreciate your help! i dont know much when it comes to things like this! i wish i could get a pic on here, my truck is 1 of a kind! thanks again
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Offline beastie_3

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Re: top speed of 79mph? wth? rear end gears?
« Reply #7 on: May 28, 2011, 11:31:26 pm »
count the teeth of the pinion and ring, then divide one into the other to get the gear ratio, but it should be stamped on the ring.
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Offline malibu795

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Re: top speed of 79mph? wth? rear end gears?
« Reply #8 on: May 29, 2011, 02:07:38 pm »
Why count it stamped in the ring gear tooth count
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adam wildman
75 K25 383/400
79 malibu 454/T56 305rwhp/432rwtq 15.6@92.8mph
02 2500HD D-max/allison best time 13.77 @ 99mph 463rwhp/930rwtq

Offline beastie_3

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Re: top speed of 79mph? wth? rear end gears?
« Reply #9 on: May 29, 2011, 03:11:41 pm »
thats why I said it should be stamped....
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Offline VileZambonie

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Re: top speed of 79mph? wth? rear end gears?
« Reply #10 on: May 29, 2011, 09:55:48 pm »
driven over drive = :1

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Offline 1979C20

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Re: top speed of 79mph? wth? rear end gears?
« Reply #11 on: May 31, 2011, 05:27:25 am »
Your speedometer could be wrong if the rear end gears are different than stock. What type of phone do you have? If you have an android phone, download a gps speedometer and check your speed with that.
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Offline 84scottsdale454

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Re: top speed of 79mph? wth? rear end gears?
« Reply #12 on: July 24, 2011, 08:37:44 am »
I used 2 diff speedometers on my droid phone! I'm sure any idiot could determine they were low,thanks for the reply "79"! Now I'm runnin 3.08s and they seem perfect! I can't still smoke the 22s at 20mph kickdown
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Offline chevymanrob

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Re: top speed of 79mph? wth? rear end gears?
« Reply #13 on: July 24, 2011, 12:43:48 pm »
4.56s even with a 26" tire and 79 mph should be about 3800 rpm. if your engine wont turn past that you may have some MAJOR issues. i think the "buy a tach" advice was the best thing said to this point.
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Offline 84scottsdale454

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Re: top speed of 79mph? wth? rear end gears?
« Reply #14 on: July 24, 2011, 10:42:29 pm »
i dont feel the need to buy on tachs look TACH-Y, i know how to blow a motor up and to keep from doing it. i solved the problem with 3.08s and my motor runs flawless and is practically new so maybe my phone is a turd or something! either way THIS MAN IS HAPPY LOL
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