Apparently it’s not that easy. That’s what I’ve wanted to do all along. You’ll find reasons in this thread.

 

I have seen reasons why converting to SRW could be challenging, as in using 4 of the same size wheels, but I haven't seen anything posted as to why going super single is not possible on the 350. Unless I'm mistaken on what super single actually is. I thought that just meant using a larger size single wheel in the rear, one that fills the dually fender, and a different size up front.

 

He would need a custom wheel. The truck is pretty high mile so he wants a new one 🤷🏼‍♂️.


285/70/19.5 is going to slightly exceed the rear gawr of a 450 cab and chassis but be well under a 550 gawr, so a 550 wouldn’t be like ‘legal’ exactly.

The Continental HD3 in that size is good to 81mph. M rating

As far as Pickup vs C&C $$:
Crew cab diesel 4x4 the Lariat 450 pickup is right at $1,000 more and comes with more power and 4.30 limited slip (c&c has 4.10).

The XL pickup is actually around $1000 less, more power, aluminum wheels and 4.30.

You get the bed, 5th wheel hitch, and aluminum wheels to sell. The XL also comes with aluminum wheels.

You get more bed width with the pickup (wider axle) and 10 inches more length with the chassis cab.

I would go C&C if you want something like a 7.3 Supercab. If you want a diesel crew cab the pickup 450 is a better value and you get the 4.30 as opposed to the 4.10, will want the 4.30 with 36” tires but not any more gear.

Downside to the pickup is 10,000 rear gawr and that takes in account the chassis and springs too.

 

Also the cab to axle length is very similar between them. So there isn’t really a change in dynamics there. Forget but I want to say its 2-4 inches.


The chassis cab is just longer.

 

I have a SRW converted 450. I am running Stazworks wheels. They are made so the truck is running a "square" set up. So all the tires stick out the same and run in the same track.

If I were you I would call Stazworks, and ask them to make you a custom set up for a 350. As the 350 is an 8 lug and not a wide track like the 450 it would require different wheels. Lots of people make wheels to convert a 450/550 but not so many for a 350.

Your front wheels would need a lot of negative offset to match up with the rear wheels.

No need for custom running gear.


Also 2 things to consider with the C&C:

1. Detuned 6.7 it's a noticeable difference. I use a lot of 550s at work, and they are pigs. Turbos spool reeaaall slow. But I'm sure there's someone who could tune it up.

2. C channel straight frame. On our work trucks on the free way there is a noticeable ride quality difference between my pickup 450 and the 550s C&C. There is a bit of frame bounce when traveling at speed. My 450 pickup doesn't do it. Also the frame doesn't go up and over the rear axle like on the pickup. So less suspension travel. The leaf back on a 550 is no joke. Rough riding. Even with a load. I would consider doing liquid spring or some sort of air ride.

The pickup 450 doesn't have much for payload compared to a 450/550 C&C but is running the same axles..... So.... If your a numbers guy, take that into consideration.

 

Whats the payload on a typical 450 pickup? My F350 dually is pretty high in my opinion.


I know you should avoid heavy steel flat beds with the 450 pickup. The front axle misc starts cutting into payload pretty quickly.


But if the payload is around 5,000 he should be fine I would think.

 

My understanding is they’re the same payload. Either way, a 350 or above will fit my needs with plenty to spare. My camper will be < 3000lbs. So not a concern.

 

Exactly, the cost as compared to the mileage has to make sense. If converting the 350 isn’t simple and cost effective, it doesn’t make sense anymore.

 

Yeah thats a lot of miles.

If you can get a new one. I would look hard at the XL 450 pickup, pretty good value. Do a conversion off that.

 

So if I did a 450 C&C with a 7.3 gasser, it isn't derated?

• What's everyone's thoughts on gas vs. diesel? Between a $10k upfront cost, $3k delete diet, and added fuel cost + repairs...gas starts making sense to me.
• Any tunes out there that help on the fuel economy?

 

They rate them differently in the c&c but are mechanically the same. And you will want a tune on it as well, I used 5star in the past on my gasser.

Referring to the 7.3.

If you aren’t towing that is the way to go. You get the 4.88 and can run a 40” tire (335/80/20) and the gearing will be fine.

 

The 7.3L in the C&C is just electronically limited, no mechanical difference. You get all the torque before it starts dropping off, you just dont get all the HP as thats achieved beyond the rpm its limited to. Was a non issue for me towing a 21k excavator on an 11k trailer behind my F550.

 

A F450 (or 550) chassis cab with 7.3 is an excellent choice for hauling large truck campers. Chassis cab F450 runs a shorter and heavier spring pack compared to F350/450 pickup. Add the lighter 7.3 engine, and that is a great config for that application.

 

Will it run the Continental 41" MPT81's? My biggest concern is the economy as well as missing out on the dual tank option of the diesel. Are there aftermarket replacement tanks that hold 60 or so gallons?

 

Yeah so that would be effectively like a 3.73. So it would work like a 3.73/7.3 gas drw 350.

I would try to find a tire with an M speed rating.