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Old 01-11-2008, 05:21 PM   #1
bad_turbo
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Wink gear and tire combo

I'm running 37 inch tires, 4.56 gears on my '67 burb with a 250 under the hood and a 4 speed trans. It seems to be under powered around town but the motor seems to wind out at 55 on the freeway. Does this sound normal?
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Old 01-11-2008, 09:13 PM   #2
k14burb
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Re: gear and tire combo

Yeah, I've got 37s and a four speed in my '66 Burb and it winds out pretty good on the freeway with 4.11s. Here's a calculator to figure out your rpm. http://www.ringpinion.com/Calc_RPM.aspx
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Old 01-12-2008, 05:08 AM   #3
Burt4x4
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Re: gear and tire combo

Toss a 454 in there and you'll be fine
4:56s are not that hwy friendly
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Old 01-12-2008, 05:51 PM   #4
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Re: gear and tire combo

Do you mean "wound out" like won't excelerate anymore, or is revved way to high? Cause you should only be at about 2300 rpm at that speed, which is nothing.
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Old 01-13-2008, 12:53 AM   #5
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Re: gear and tire combo

We`re all used to hearing rpms from overdrive equipped vehicles on the highway.I roll @ 3,000-3,200 rpm all the time.
I think the 250/37s/4.56 combo should run about how you say it is.
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Old 01-13-2008, 02:56 AM   #6
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Re: gear and tire combo

Quote:
Originally Posted by bad_turbo View Post
I'm running 37 inch tires, 4.56 gears on my '67 burb with a 250 under the hood and a 4 speed trans. It seems to be under powered around town but the motor seems to wind out at 55 on the freeway. Does this sound normal?
Same tires/gears I'll be running this summer but I'm throwing a 700r/241 in the mix.
That will get me to around 1800rpm w/37's or about 1900rpms w/36's @ 65mph.
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Old 01-13-2008, 04:09 AM   #7
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Re: gear and tire combo

Drop in a NV4500, and get a bottle, problem solved.
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Old 01-13-2008, 08:38 AM   #8
bad_turbo
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Re: gear and tire combo

thanks guys for all the help and info. Heres a pic of the beast!
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Old 01-13-2008, 10:13 PM   #9
earl87gta
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Re: gear and tire combo

My 68 sounded like it was coming apart at 55 MPH but i tihnk it is do to the rock well transfer case more then gears. Im swithing to a 205 and nv4500.
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