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I am going to be changing the gears in my 86 bronco soon, so I can restore some of the power to the wheels. I know a stock 86 bronco's top speed is around 89mph, and I need to know if after regearing, will I be able to Still drive on the freeway, and what the top speed would be.
 

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There are a few variables involved (i.e., condition/performance of motor/tranny, actual weight/mass of tires/wheels, mass/weight added or removed to/from vehicle, etc.), so it would be nearly impossible to determine the exact top speed.
The 4.56 gears/35" tire combo will put you back relatively close to the stock ratio, so you should be close to stock performance levels, assuming all else being equal.

Should not be a problem maintaining freeway speeds.
 

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Gearing wise if your an auto c6 combo should be around 105 @ 5k rpm.
http://www.grimmjeeper.com/gears.html
Best calculator I have found, but like mentioned above there is a lot of variables to consider.

Where did you see that a stock one will only do 89?
 

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What transmission do you have? Whether or not you have overdrive will make a difference.

But, to calculate your RPMs:

RPM = (Speed * Transmission Gear Ratio * Final Drive * 336) / Tire Diameter

If you have a non-overdrive, have 35" tires, a 4.56, and want to go freeway speeds (75?):

RPM = (75 * 1 * 4.56 * 336) / 35
RPM = 3280

A little high, you won't be netting any great gas mileage, but you should be able to maintain that speed just fine.
 

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Discussion Starter #5
Gearing wise if your an auto c6 combo should be around 105 @ 5k rpm.
http://www.grimmjeeper.com/gears.html
Best calculator I have found, but like mentioned above there is a lot of variables to consider.

Where did you see that a stock one will only do 89?
Here is where I saw the top speed:
http://www.automobile-catalog.com/car/1986/1488560/ford_bronco_5_0l_efi_v-8.html

I have a 302 with a Borg Warner transfer case transmission I believe is a E4OD
So it's a small engine for a big truck, and I can barely keep up with people on the highway as is right now.
 

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Here is where I saw the top speed:
http://www.automobile-catalog.com/car/1986/1488560/ford_bronco_5_0l_efi_v-8.html

I have a 302 with a Borg Warner transfer case transmission I believe is a E4OD
So it's a small engine for a big truck, and I can barely keep up with people on the highway as is right now.
86 will be an AOD (non-computer controlled) tranny.
The reason you can barely keep up is 'cuz you got big azz tires and weenie little gears. The 4.56's will fix ya! :thumbup

Until you swap gears, stay out of overdrive. This will put you closer to the rpm's you would experience with the 4.56 gears while in overdrive, and will put the engine closer to it's powerband. You will find keeping with traffic on the freeway a little easier. ;)
 

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86 will be an AOD (non-computer controlled) tranny.
:stupid

The reason you can barely keep up is 'cuz you got big azz tires and weenie little gears. The 4.56's will fix ya! :thumbup
:stupid

Until you swap gears, stay out of overdrive. This will put you closer to the rpm's you would experience with the 4.56 gears while in overdrive, and will put the engine closer to it's powerband. You will find keeping with traffic on the freeway a little easier. ;)
:stupid
 

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Definitely agree with 4.56, in your situation. I run them with 33's in my '05 150, and had them in my '01 F150, with 35's. Sadly the little 4.6 2v is the same, and the '05 is far heavier. :(
 

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I have an '87, C6, 33s and 4.56 gears. I have no problem at freeway speeds (which is 75mph max for a truck of this size as far as I'm concerned). Turns over about 3750.
 
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