68 f350 DRW 2wd to 4wd conversion

[briansbronco]

OK guys, first off great site and I have been lurking for a good long while. Lifetime ford guy with lots of builds under my belt. I need a little help with a recent purchase. Just picked up a 1968 F350 DRW cab and chassis truck that has a service bed on it currently. Interested in converting it to 4x4 in the very near future. I know that there is affront axle that will give me the least resistance with the swap and I am asking the question here to save me countless hours in the wrecking yards looking. So what have others done? I searched extensively and the only thing I could find was a crewcab build but it didn't give any specifics on the front axle used. Just that it was swapped into a 2wd. Need at least a heavy 44 or 60 dually front axle. This truck will also be getting a cummins conversion while in the shop next week. have a divorced 205 to take residence behind the np 435 in the truck to get that taken care of, just need to get some input on which front axle to start with. Don't want to pull the cab or cut the frame and splice and I also know that is the standard answer. This truck is VERY straight for the age and I have had the designs in my head for going on five years for my new daily driver truck. Girlfriend want to keep the service body instead of a custom flatbed that I pictured but hey....it might be ok.

[eggman918]

I doubt you will be happy with the gear spacing in the 435 behind the Cummins it will be VERY uncomfortable to drive,since you are running a divorced T case you should think about a 5 speed with overdrive.When I put the 4BT in my '68 I started with a 2x4 M5odr2 and was very happy with the gear spacing in it but it did not hold up well to the loads I was towing so I went with the ZF 5s42 again 2x4 it is not a close ratio like the M5 but muck better than the 435.With the m5 I shifted a ~2100rpm and with the ZF ~2400rpm but still very driveable,and with the .76 OD and 3.55 gears on 33" tires I cruse at 2,000rpm @ 75mph netting ~20mpg.For a front axle idealy you want a '78/'79 Ford D-60 its a direct bolt in. Your best bet for a trans is either a ZF or NV-4500 depending on what adapter comes on the engine if you are planing on the 6BT find a dodge with the 5 speed and get engine/adapter/bell housing and trans as well as the intercooler you will save a lot of cash as adapters alone run from $600.00 to $1,500.00 or more depending on what trans you decide to run.The B series Cummins's get there best mileage at 1,800rpm and mine lives between 1,500 and 2,400 with 95% of it's time between 1,500 and 2,100 so gearing is very important to your drive ability this is the gear calculator I like best http://www.grimmjeeper.com/gears.html
Check it out and play with various combos BEFORE you start buying parts..........trust me on this you will come out WAY ahead in the long run

[cep62]

a '78/'79 Ford D-60 its a direct bolt in.

Not for a 2wd conversion it wont be.

One of the truck shows got a Dodge chassis 1 ton with a Cummins and put a "79 ford cab on it.
their theory was the frame and drivtrain were matched and stronger than converting a gas frame.

A "79 bolts up like "68 does.

[hazelnut]

The major problem is going to be the frame of a 2wd vs a 4wd. The 2wd has that big cross member right in the middle if the engine, Where as a 4wd has the cross member that in front of the engine. I've seen many members put cummins in 4wd's and only 1 put in a 2wd. That one was a F350 and was a lot of extra work because of the cross member.

Here's a members F350 2wd that they installed a cummins into. http://www.fordification.com/forum/view ... 22&t=48572

[briansbronco]

Thanks for the replies guys. Couple things, Maybe I should have mentioned that I am a cummins certified tech, I'm good on the cummins swap. I will be sticking with a 4bt, not a 6bt, for various reasons. I know that I can get 200 hp from a 4bt without much trouble and would rather save the weight. The transmission will remain an NP 435 for various reasons as well. If at any time later I need to trade out for an overdrive (it will most likely not happen) the divorced transfer case will make it a very easy mod. That I one of the reasons for going this route instead of a married unit. This has worked well for me in the past with other builds. For my direction and plan the combo of the 4bt,NP435,NP205 is the best of scenarios. I have ran the numbers and looked at the ratios. I have also worked with this combo before so I am aware of the rpm gap with the transmission. I just mentioned the 4bt to give the direction of the build more than anything else. Getting the 4bt into the f-350 frame was already thought through. I like this truck enough to do whatever needs to happen to get it where I want it.


So back on point, and the reason for the post. Will the 79 d-60 swap into the f-350 directly? This was my early contention as well but I didn't want to source one to find out it wasn't the best option out there. I know there are guys that have more knowledge than me in this area. I would love to hear from someone who has done the swap with details.

Thanks again for the input. Keep it coming.

[briansbronco]

I am looking to keep the front coil springs if possible. Doing a leaf spring swap is the last resort to get the front axle in for the 4x4. So what I am looking for is a front dana 60 or eight lug 44 with the same spring perch center as the 68 f350.

[Ranchero50]

If you can get the '79 D60, try to get the rest of the front suspension or even lop the front of the frame off so you can graft the cross member in place. The 2wd crossmember has to go regardless unless you plan on running a huge lift which isn't going to play well with the coils. At a certain point the return isn't worth the investment vs. just installing the leaf front end.

[briansbronco]

I was planning a 6" lift, or at least to clear 37" tires. I live in the mountains of Montana and this truck will see more crawling up steep hills and embankments in the back woods than highway time. From the pictures that I took before I left home (I am five hours away from my truck right now) I believe that the cross member can be modified to allow more clearance without having to ditch it all together. We'll see I guess but that is/was the plan.

[briansbronco]

It's funny to me how things have a way of changing quickly when you start sourcing parts. I was offered the whole drive line from a 95 3500 dodge today for cheap and I am not sure I will be able to resist. 95 12v, nv4500 with transfer case still connected. This might be too much to resist.

[briansbronco]

Update: Went after a load of straw bales today and saw a 70 f250 4x4 sitting in a driveway with a for sale sign in the window. Ten minutes and 800 bucks later I was driving it home with one of my farm hands going to get the straw bales for me. My 68 is so straight, clean and nice that I never really wanted to mod it but I was working with what I had. Now that I picked up the high boy plans might be shifting to it instead. It is a little bit of a beater but a solid truck and it already has a flat bed...LOL.

[briansbronco]

P.S. I might have some kind of addiction that needs medical attention. That makes five in the bump stable.

[1972hiboy]

P.S. I might have some kind of addiction that needs medical attention. That makes five in the bump stable.

It happens,

[briansbronco]

I know I have let this thread die a little but I am back on it again. My 70 highboy has become my full time mountain plow truck and now I am looking again to Mod the 68 dually. Playing with it any in my area requires tire chains until march nearly and it is pissing me off more than anything else. Getting down my driveway is one thing, getting back up the two miles, even plowed has required chains every single time and I am sick of it.

So in the time that has passed I have basically rebuilt the 360 in the dually. It is running very strong now and I want to leave it alone. I am not giving up on the diesel swap I am just back burnering it for now. Concentrating on converting to 4x4 as of now it is not a want, it's a need.

So there were some comments earlier about just converting to leaves up front. What have others used up there to make the truck sit relatively level? A little bit of lift isn't going to hurt anything as that was always the plan. I know that chevy dodge and ford all have divorced transfer cases and I would much prefer to use a 205 if I can find it. So what front axle is going to give me the least mount of trouble going under the f-350? Ideally I would like something that has spring perches that are the same as the frame rails but I know that might be wishful thinking.

What say you?

[cep62]

Have you thought of these people?

http://www.napco4x4.org/

It looks like its pro gm , but Napco did Ford conversions too.

[carnuck]

I joined the Napco4x4.org forum recently to find out about converting a different 2wd to 4x4 (my motorhome) and apparently the Dana/Spicer 24 is popular for doing the NAPCO conversions. (there is a clean used D24 setup posted on feEbay that mentioned it before I joined that group)

I would be tempted to swap the DRW axle into a Highboy 4x4 with the '68 body on the frame and IIRC, you can bolt the 2wd drum spacers on the front D44 of the highboy and use your current offset matching wheels.