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Discussion Starter #1
I have a stock 1988 F150 4x4 ( i know its not a bronco but I have one of them already and she is built up nicely ) Anyhow I am running the stock from axle in it. I am swaping in a built 9 inch with a detroit locker and 3.50 gears. But im having trouble finding the 3.50 gears for the front can anyone help me PLEASE. any places anyone knows that would sell them or anyone who has a set that would work. thanks a ton

mike
 

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You more than likely already have 3.54 in the front. You will not find the exact number for the front to match the rear. Unless your truck came with a different gear ratio but most 4x4 trucks came stock with the 3.50 ratio.
 

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kibblepup83 said:
I have a stock 1988 F150 4x4 ( i know its not a bronco but I have one of them already and she is built up nicely ) Anyhow I am running the stock from axle in it. I am swaping in a built 9 inch with a detroit locker and 3.50 gears. But im having trouble finding the 3.50 gears for the front can anyone help me PLEASE. any places anyone knows that would sell them or anyone who has a set that would work. thanks a ton

mike
9 inch did have 3.50 gears and you cn get them at Randys Ring and Pinion http://ringpinion.com/content/products/default.asp?vid=3&pid=4


good luck,

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Discussion Starter #5
any have any sugjestions what ratio to use. I want a very good pulling gear but something thats not goin kill my gas milage cause its still goin be a daily driver now and then. but want something thats goin give me a bit more pulling force and ass. I have been fabricating things for 4x4s and working on them for years now but am just now getting into great ratios and front and rear diff's can you guys help me understand the ratios and what not better
 

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When I said 3.50 for 9" I actually mean 3.50 not 3.54. If you have a 9" rear end, you may infact have 3.50 gears in it.

What you are asking is not a short story. The best gear ratio is sort of subjective. Basically, you need to know what RPM you need for whatever you are using the vehicle for. A rock crawler would use a completely different set of gears for the same RPM than a road machine would. If you are going to run on the road, then optimum cruise RPM for Ford truck engines is between 2000 and 3000 RPM. The lower end of that yields better milage and the upper end yields better power.

If you look at Jeff's Bronco Graveyard 80 and up catalog, he has a great chart covering this. Just keep in mind his chart is calibrated for 55 MPH cruise speed. So if you cruise at 65 then you have to recalculate the numbers. Fortunately for you, he gives a good formula to do that. http://www.broncograveyard.com Download his catalog and look at page 42.

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Over drive allows you to use a higher gear ratio for the power stuff while helping out when cruising. What I put in the last post is just a scratch on the surface. If you really want to understand all the ramifications of how different things effect each other. Basically, you need to get some books if you really want to understand.

I've left a whole lot out and don't have time to post enough to really educate you. Read the comment on communications in my post :)
 
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