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03-12-2015, 03:23 PM
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#1 |
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Registered User
Join Date: Apr 2014
Location: Birmingham, AL
Posts: 560
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NV4500, SBC, 4:10 and MPG
Currently I have a 1972 C20 with a 1989 C3500 front end and a 4:10 rear end. The tires are 225/70/19.5 (dually). The motor is a 383 SBC bored over 30 with a holley carb. It has a low cam (not sure of the numbers), stock manifold and dual muffler.
Now I am running a TH350 but my plan is to do a lot of heavy towing. The tranny is excellent shape now so I want to go ahead and install a NV4500 gearbox before I mess it up. What sort of mileage will I be seeing with this gearbox? I am no longer a pedal to the metal person  .Thanks for your help. |
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03-12-2015, 03:37 PM
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#2 |
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Senior Member
 
Join Date: Apr 2008
Location: Franklinton NC
Posts: 1,309
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Re: NV4500, SBC, 4:10 and MPG
I am thinking 8-12 mpg.
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03-12-2015, 03:41 PM
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#3 |
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The Older Generation
  
Join Date: Aug 2006
Location: Montezuma, Iowa
Posts: 25,771
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Re: NV4500, SBC, 4:10 and MPG
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I'm thinking a little more than that. What ever you get it will be easier on the engine.... LockDoc
__________________
Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 - |
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03-12-2015, 04:23 PM
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#4 |
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Registered User
Join Date: Dec 2012
Location: Chandler AZ
Posts: 1,149
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Re: NV4500, SBC, 4:10 and MPG
First the with TH350 you'll have around a 20% loss in drive train. Second TH350 is 1:1 final drive.
NV4500 has 15-17% loss so you get a small gain. NV4500 also has 1:.73 final drive as well as a deeper first gear. Take off whilst pulling should be more effortless. Cruising down the freeway with the overdrive should give you the ability to have better economy by working the engine less. You may have to find how it "likes" to be driven to get the best performance.
__________________
1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9 |
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03-12-2015, 08:19 PM
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#5 |
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Registered User
Join Date: Apr 2014
Location: Birmingham, AL
Posts: 560
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Re: NV4500, SBC, 4:10 and MPG
WOW, I was hoping for 16-20 mpg, lol. Thanks, I will be going this route anyways so it can be easier to pull the weight. :-)
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03-12-2015, 08:36 PM
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#6 |
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Registered User
Join Date: Oct 2008
Location: Marianna Arkansas
Posts: 7,280
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Re: NV4500, SBC, 4:10 and MPG
A 20MPG 3/4 ton? We can all dream. The overdrive is def gonna help but not that much, But your drive train will seem to be in less strain all the time. Jim
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03-13-2015, 09:56 AM
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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: NV4500, SBC, 4:10 and MPG
My '72 K2500 350/TH350 4.10 235/85-16s truck gets 12.5 mpg. The '72 K/20 I had with SBC400/4spd 4.10 315/75-16 truck got the same. I am sure the NV4500 will get you a good bit better than that with a well tuned motor
__________________
"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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