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08-04-2008, 08:56 PM
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#1 |
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Registered User
Join Date: Nov 2005
Location: Monroe,Georgia
Posts: 313
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3.08 vs. 3.73
I have an NV3500 with a .73 5th gear. I have 3.73 gears now. First gear is so low geared I hardly use it other than starting on hills. I have 27" tires. I want to put 3.08 gears in it. Does anyone have this combo? I have a 355 with about 300hp so I think the low rpm at highway speed won't be hard to maintain.
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08-04-2008, 09:46 PM
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#2 |
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Registered User
 
Join Date: May 2008
Location: Granbury, TEXAS
Posts: 250
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Re: 3.08 vs. 3.73
My calculator says you will go from 60 mph at 2000 rpm to 72 mph. SHould work ok. You will have to change the carrier to a series 3, more $$$ than just a ring and pinion.
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Mine is chopped, has a clutch, and a big block. |
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08-04-2008, 10:01 PM
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#3 |
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Special Order
  
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,851
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Re: 3.08 vs. 3.73
1st is an underdrive.Figure on 2nd gear starts under normal driving.
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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08-04-2008, 10:07 PM
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#4 |
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its all about the +6 inches
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,690
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Re: 3.08 vs. 3.73
1, 2 and 3 are all underdrives.
 If you drive at 70 MPH, then it may work out OK. If you drive at 60, your MPG will probably get worse, not better. |
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08-04-2008, 10:56 PM
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#5 |
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Special Order
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,851
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Re: 3.08 vs. 3.73
What I meant was 1st is a creeper gear.
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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08-04-2008, 10:58 PM
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#6 |
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Senior Member
Join Date: May 2001
Location: West Central Minnesota
Posts: 568
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Re: 3.08 vs. 3.73
I'd stick with the 3.73s, I don't think you'd get much use out of a 3.08 with a .73 overdrive. I've got a couple of 3.08s and they're marginal with a 1:1 final gear, pretty much worthless for towing anything but a light trailer. 3.08 x .73 = 2.25, that's a pretty high gear.
Bob
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V-6....only GMC Trucks have it! 62 GMC W5000 NAPCO-V6 65 GMC 2500 NAPCO Panel-V6 66 GMC 1000-V6 66 GMC 1500-V6 67 GMC K1500-SBC (originally a KM-V6) 68 GMC C1500-V6 68 GMC C1500-V6 68 GMC Suburban C2500 70 Chevy K20-SBC 71 Chevy C30 Longhorn-SBC 72 GMC Suburban C1500-BBC 72 Chevy C10-SBC 72 GMC C5500-ToroFlow Diesel |
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08-04-2008, 11:06 PM
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#7 |
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Special Order
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,851
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Re: 3.08 vs. 3.73
I agree with Bob.I think of a truck with 3.08s as overdrive.You need bottom torque to get them rolling.I wasn`t thinking about the rear,but the transmission in my last answer.When I saw the title my first thought was,"What about 3.42s?"I consider that my threshold for o/d.It`s not bad w/o and can still pull with o/d as long as you have low-end torque.That`s how most Tahoes come ,as far as what I`ve seen.That should give you some idea of where they lie.It`s not a heavy hauling set-up,but can tow.
I run 4.10 & o/d in my one ton and love it.Hauls loads ans hauls azz.Can`t beat that!
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 08-05-2008 at 06:57 AM. |
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08-04-2008, 11:25 PM
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#8 |
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Senior Member
Join Date: Mar 2003
Location: Colfax-California
Posts: 8,630
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Re: 3.08 vs. 3.73
3.73 gears times .73 equals a final drive of 2.72. The 3.08 times the overdrive comes out to 2.15. I'd keep the 3.73s
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