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MD
Dodge Dakota
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3/04/2003
23:47:02
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 Subject: Gear Ratio For 4.7
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In an earlier life I used to tow a "C" Gasser '57 Chev to every drag strip in California - Lions in Long Beach, Pomona, Irwindale, Half Moon Bay, etc.
I ran a 292 ci (.030 overbore on a 283 ci block), true ram air induction on Hilborn injectors, and the 3rd set of headers that Gary Hooker ever made. An Isky roller cam, forged pistons, hardened crank - the whole 9 yards. Then I went to Cal Berkeley to study math. Oh well.
The point is, that little chevy block screamed out RPM, but had comparatively little low end torque or HP, I ran 5.38's in the rearend - it made it's power on top end. Sound familiar?
2 weeks ago I had 4.10's installed in my 4.7 Dak. These are the gears the truck should have had out of the factory - not 3.55's (not the 3.90's either - I know, I know; only about 150 RPM difference at 60 mph; but on a "top end" engine that is significant).
One can spend a bundle on internal and bolt on engine mods, but if your 4.7 is equiped with 3.55's the single BEST mod you can make is to go 4.10's. 4.56's if you are going the tall tire route.
Just thought I would share my opinion.
MD
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greenmr
Dodge Dakota
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3/05/2003
12:55:54
|  RE: Gear Ratio For 4.7
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I've been toying with the idea of swapping gears, but I also drive anywhere from 15-20k miles a year so I have to keep fuel economy in mind. Have you looked at / noticed a change in mpg on your truck since changing your rear end?
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Jaggy
GenIII
3/05/2003
13:09:46
|  RE: Gear Ratio For 4.7
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Thanks for the input MD, I want to put a 4:10 rear end in my DAK but alas I have a 4x4 and can not get gears for the front diff. If you know of a place that sells them, or makes them please let me know.
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MD
Dodge Dakota
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3/05/2003
22:27:04
| RE: Gear Ratio For 4.7
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Greenmr - I have not noticed a real change in mileage - I am still on the 1st fillup since getting the gears. Just eyeballing the needle and being familiar with where it normally rests at a given number of miles, I can't tell a difference. I sense that I'm making slightly better in town and slightly less on the road - I doubt if there is a 1 mpg difference either way. Driveability is MUCH better - with the 4.10's and anything approaching stock tires you ca n motor along over fairly steep terrain at 65 mph and the auto stays planted in OD - no more constant searching for the right gear.
Now, for the question by the other gentleman about 4.10's not being available for the front - I have been told that is true - HOWEVER - if you have 3.55's now and can afford to do so, GET RID OF THEM. I think the 3.90's can go into both ends, and that would be a HUGE improvement.
MD
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jaggy
GenIII
3/07/2003
15:47:21
| RE: Gear Ratio For 4.7
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I talked to Randy's ring and pinion,
4:11 and 4:56 are being tested right now.
$460 for front and rear and minimal install kit.
they should be out in about a month.
I spoke with a mechanic and it looks like about a 13 hour job by the book.
thats around $700 labor.
I have a month to line up a mechanic by Randy's Ring and Pinion is going to call me as soon as the gears are available.
I will keep everyone posted.
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MD
Dodge Dakota
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3/08/2003
01:04:28
|  RE: Gear Ratio For 4.7
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Jaggy, that sounds great - 4.10 is the gear - just don't go crazy on tire size - you don't want to end up back where you started.
Good luck,
MD
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