E350/450 Cab-Chassis w/ Composite Box Body - Feedback Requested

[luthj]

Hey gents, I am planning to build a 84" wide by ~14ft composite box on a chassis. GVW in the 11klb range. Considering medium duty cab over engine trucks and vans.

The intent is for full-time occupation for years at a time, and will be used for international travel. I like the E-series due to the gas powerplant, and option for reliable 4x4 (UJOR etc).

I am looking for some feedback on the E-series, as I am not intimately familiar with the platform. I know this is the van sub-forum, but there is probably more E-series experience here in general.


Track width, wheels etc:

Looks like the E350 SRW (cab chassis) has a hub-hub width of about 73"? Confirmation would be great though.

Typical 4x4 swap front axles are about 70" hub-hub width?

Looks like method 17" wheels with zero offset are a readily available option. (single rear wheels are a requirement for us).

Axle loads:
Any issue running 4,500-5000lb front axle load with a D60? No chassis issues with that weight?

General Questions:
Issues with the 7.3l gas and 6 speed trans? Anything to be aware of?

Fuel economy expectations with 35" tires, 4x4, and 84" wide by ~89" tall box? I see some small class Cs in the 11-12 range with conservative driving. Seems high with the 7.3L, but that's just a gut feeling.



Anyways, I will dig through the thread archives as I have time, but any useful links/threads would be greatly appreciated!

 

[RVflyfish]

Two of my favorites…

Calgary McLean’s

PathNotTaken’s

 

[iggi]

The width of the Econoline is narrower than the F series so this seems wrong: "Looks like the E350 SRW (cab chassis) has a hub-hub width of about 73"

I still had a tab open from looking up axle widths a few days ago:
The hub-to-hub width for a 2005 Ford F-350 Dana 60 is approximately 69.8 inches, with the WMS-to-WMS (wheel mounting surface to wheel mounting surface) measurement being 72 inches.

My annual average fuel economy is about 14mpg.
As a point of comparison, I'm coming in about 10,000 lbs, 2WD, 32" tires and a 6.0 Powerstroke.

I'm six years with my E350. Other than how much of a PITA it is to work on the engine it's been great.

 

[luthj]

The width of the Econoline is narrower than the F series so this seems wrong: "Looks like the E350 SRW (cab chassis) has a hub-hub width of about 73"

I meant to put "rear" axle in there. As the SRW cab-chassis has a wider rear track than the vans, with the DRW being even wider I believe. (75"?) The SRW is a bit harder to calculate the hub-hub distance due to the offset, but factory wheels being about 10-15mm, puts its around 73".

 

[luthj]

Did some weight distribution math, looks like my planned 14ft box will just work weight wise. This includes the weight of a 4x4 conversion, and 34" wheels and tires, plus water, food, passengers etc. Load range F tire is good for 7940lb, so there is a bit of margin. I would like a touch more weight on the front axle, but there isn't much to be done with a 158"WB and a longer box.

 

[Blackdogvan]

Best single tire options I've found is the Toyo Mud Terrain 37X13.50R17LT - 4300lb rated. It's a bit of a unicorn in the LT tire world but quite a few other options around 4000lbs.

You might check out Mesa Overland who is building a E350 from U-Joint at this time for inspiration on your build.

I think 4x4 converted they are a really great option due to their payload capacity.

 

[luthj]

I do see some 35s with ~3700lb load ratings. A few choices in the 37" range with ~4,000lb load range. I think 3,900lb should be fine with a decent margin.

Toyo does offer a the Open Country R/T Trail in 295/70R16 with 3,970. Which seems like a decent choice, and isn't lifting the vehicle to the moon.

I am curious about ride quality with UJOR conversions. I know its not going to ride like an IFS coil spring setup, but I don't want to hate myself after a 3 hour drive either.

 

[ujoint]

I do see some 35s with ~3700lb load ratings. A few choices in the 37" range with ~4,000lb load range. I think 3,900lb should be fine with a decent margin.

Toyo does offer a the Open Country R/T Trail in 295/70R16 with 3,970. Which seems like a decent choice, and isn't lifting the vehicle to the moon.

I am curious about ride quality with UJOR conversions. I know its not going to ride like an IFS coil spring setup, but I don't want to hate myself after a 3 hour drive either.

Come for a ride at one of our shops.

 

[luthj]

Thanks for the offer. Closest to me is CO (11 hour drive). If I end up that way I will drop by!

 

[luthj]

Looks like the E350 158WB SRW uses an oddball rear axle with a ring gear offset incompatible with locker options? Unfortunate if that is the case. I can't find for sure confirmation, as most of the prior results on the web are for the vans, not the cab-chassis.

 

[iggi]

Looks like the E350 158WB SRW uses an oddball rear axle with a ring gear offset incompatible with locker options? Unfortunate if that is the case. I can't find for sure confirmation, as most of the prior results on the web are for the vans, not the cab-chassis.

I'd go from the BOM number.

Dana 60 BOM Numbers | Dana 60 Identification

Crawlpedia is an off-road encyclopedia featuring a complete list of Dana 60 Bill of material (BOM) codes with complet axle details.

www.crawlpedia.com

 

[luthj]

Thanks for the feedback folks.

Ended up buying an E350 SRW 158WB, and having it built by Ujoint. Will start with a more basic chassis build, factory bumper, 34" tires. Might end up changing that once we get some usage in, but overall height and managing fuel economy loss was somewhat important.

Interior build is going to be done by me, will take about a year to something mostly complete. Full time travel is what we do for years at a time. So its going to have >1kw of solar 75-100gal of water, high efficiency AC, diesel water/air heat, and a decent amount of storage.