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Discussion Starter #1
Hey yall. I might have a chance to achieve most any bronco owners dream. I'm looking at a cheep 86 f250 with the 6.9 IDI 4x4 and a 4 speed manual. Ive always wanted to do a diesel conversion but I don't know the first thing about where to start. I do know I want the f250 axles and drivetrain but keep my half ton suspension and frame. However I don't know the logistics like:
-What would I register this as after the swap? the 250 is pre smog and that would be awesome but my 79 bronco is not.
-Would I just gut my wiring and replace it with all the f250 wiring?
-And just generally where should I start if I take this project on?
 

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Well, the rear axle would be a good upgrade, but I'd stay away from the front. The '86 F250 has a Dana 50 TTB, which is quite the engineering challenge to slap on Pre-80 ( solid axle) Bronco.

I suppose you could use the Dana 50 outers, and at least keep the same bolt-pattern for the wheels. The 6.9 IDI doesn't produce enough torque to stress the D44, unless you're running 37" tires or larger
 

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In CA, you could go see a DMV referee and they would make the determination about how it could be smogged. I see (2nd hand) a lot of friends get denied because the Bronco is a 1/2 ton chassis, but diesels are coming out of an industrial vehicle (step van) or a 3/4 or 1 ton truck. Your best bet is to convert a pre '75 vehicle, or find a 1/2t truck with a diesel to use as a donor.

If I were to do this, it would be fairly simple as I live in a non-smog state. I'd pull the engine, tranny, and wiring harness, then splice in the dash as needed. Some things will plug right it, a few you'll have to customize, like glow-plug lights and similar indicators. Motor and trans mounts will need to fabricated as the frame widths are different across the 86-79 model years.
 

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Discussion Starter #4
(correction the 250 is an 84) but wow you are right about that ttb I didn't even check I just assumed it would have a straight axle. Do the 1 tons around those years have straights?
 

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hmmm. So I should be fine with my D44 up front? It's also an issue of gearing though isn't it? If I am going to do this I want to do it right. Wouldn't it be best to keep a matching pain or axles?
 

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How could it be that this is a conversion that you have always wanted to do, yet you have no idea on where to start......be careful of the good idea monster!
 

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Discussion Starter #9
Because I always thought it was kind of an unattainable goal so I never looked into it. The whatnow?
 

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Anything is possible with time and money.............8 Billion people on the planet - if you thought of it, odds are so has someone else........
 

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hmmm. So I should be fine with my D44 up front? It's also an issue of gearing though isn't it? If I am going to do this I want to do it right. Wouldn't it be best to keep a matching pain or axles?
1) Keep the Dana 44, regear to match the D60 in the back. That's cheapest, but you'll end up using different rims front an rear (front will be 5x5.5, the rear will have 8 x6.5 bolt spacing.

2) Regear the D44, but use the outer axle and spindles from the D50. I've not done it, but others here have. More work, about the same price, but all your rims will match.

2a) Some places will sell a set of spindle / hubs /axles for the D44 that will let you use the HD bolt pattern. Less work than 2), but probably more expensive.

3) Find a D60 from a pre-80 F-250 HD (not the Highboy version) or F-350. You'll have to convert from coil springs to leaf, or vice versa. An 86+ f350 will also supply the D60, and that may be simpler to convert.
 

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I would shorten the f250 frame and move the 79 body to the truck frame. I wouldn't say anything to the authorities. That old of a vehicle they would not even care. Now you wouldn't need to change steering geometry. The speedo cable should hook up to the dash. You will have some issues with the diesel but that should be easily overcome.
 

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One of the guys on here did this the easy way and simply used the entire f-250 frame and cut about a foot off the end of it. He did it in his 2 car driveway in a weekend or two. There was a really good build on this.
 

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Found it!
http://www.fullsizebronco.com/forum/showthread.php?t=195232&highlight=frame
One issue all the pictures are dead which really is a shame this guy documented almost everything he did.
There is still a quick video on page 5 of it running
http://www.youtube.com/watch?v=kOx9zRetyuE
Looks like he logged in on 12-01-14 you might be able to contact him and get some advice if you go this route.
Also looks like in one of his last posts he mentions posting on another forum so the build might still be whole somewhere.
 

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I just realized this is a 79 body. The thread I referenced was a 90's. Actually might still work have to compare the two side by side for body mounting.
 

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Discussion Starter #16
I've heard that argument before but shortening the frame and putting the bronco body on it would be pointless. That would just give you an f250 that looks like a bronco not a bronco. I would rather just drive an f250 than chop the frame.
 
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