I will take some measurements for you today. I will say that based on the picture my tailgate has more clearance when down, my wife can walk between the tailgate and the trailer (maybe not so much walk as shimmy)
My Curt 16K also had 3 positions where it was bolted to the feet. Mine is in the rearward most as well as the highest position available.

First let me correct my previous post. My hitch is mounted to the feet in the highest position of the 3 available. There is only one way that the hitch head will bolt to the feet and that is in the exact centerline of the feet front to rear. I was going off of recollection and I misremebered when I put it together.

So for the measurements, here is what I have. This is a 3500HD crew cab standard box (6 3/4') 4wd gas engine truck built in Flint MI Dec of 2020

Floor of bed to top of side rail 21 1/2" (measured from flat area around wheelhouse)
Centerline of hitch feet to rear edge of bed is 39"
Centerline of feet to front bulkhead of bed is 43 1/4 (These 2 measurement reflect the approximate rear offset of the puck system to the rear of the truck)
Centerline of gooseneck plug to rear edge of bed floor is 37 1/2" (showing that the gooseneck mount is another 1 1/2" rearward than the hitch feet centerline)
Centerline of hitch feet to the edge of the opened tailgate is 61 3/4"

let me know if theres something I missed. I intentionally left out the hitch head top to floor dimension since I didnt think I could get it accurate with the straight edges I had and the fact that all the hitches will vary slightly along with the pinbox settings factored in.

Scott

Scott,

Your first pic also confirms the hitch is aft of the centerline of the rear axle by a small margin since the rear diff is centered to the fenderwell. I read they were doing this awhile back but no longer remember where I picked that up.
Not to go off track but your towing mpg and non-towing mpg on the gasser would be interesting to know as well. I had seen this truck tested out west where they were using 85 octane fuel which would totally kill performance.

Jim

familytruckster4

Hi Scott,

Your measurement . . . Centerline of hitch feet to the edge of the opened tailgate is 61 3/4" would fit with the hitch point being slightly aft of the 62.5" center of rear axle to edge of open tailgate per the upfitter information linked by Jlawles2 Joseph.

This confirms that aft edge of a Superduty Ford open tailgate is almost 9" closer to the front of the 5th wheel than the open tailgate of a HD GM. (70.5 - 61.75) That's a lot !!

On the other side of this, the centre line of rear axle (hitch point) to cab is 40" on the Ford and 42" (maybe 43") on the GM.

Part of this is that a "6 1/2 ft box" is 85" long on a Ford and 80.4" long on a GM.

All this to say that a slider hitch is more important in a Ford than in a GM. (6 1/2 ft "short" box)

Rob

I remember a while back seeing a video where they were talking to the engineers at GM when the 17 or so came out and they were discussing the offset of the hitch platform. IIRC it had something to do with leaf springs and axle placement on the spring.

I think I saw that same video, the takeaway that I had was that they had shifted the hitch mount centerline rearward because it had minimal effect on the load capacity with the bonus of negating the need for a slider.

Note that the 2019 and 2020 models (the first puck system) were very different from the dimensions of the 2021 through current.

If you add the 2 dimension noted for the relationship of the hitch from the bulkhead to the rear edge it comes out to a tick over 82" ( I always understood it to be 6ft 9"+ on the new trucks and this measurement bears that out


As far as mileage goes.... Thats kind of a deep dive but we just got back from 11 weeks on the road where the price of fuel rose well over a $1 per gallon while we were still over 700 miles from home.
Our 337 is pretty heavy since we were packed for a few months, I had my generator in the bed of the truck 100lbs along with the trailer spare, a spare 20# propane cylinder and a 5 gallon fuel can that I kept full.
I would guess the trailer and added cargo are pretty close to 13k although I havent weighed it I would be willing to bet I am very close.
The majority of the miles on this truck are towing, I dont drive it much around town because I am retired and the car gets 31 mpg around town.
We have been from MI to FL and back twice now with some side excursions on the way down and back as welll as a trip to the rally in Goshen last yr and then to Iowa/Nebraska and then back through WI and the U.P.
I typically run 64 mph because thats what the truck seems to favor. It pulls in 5th gear with an rpm of around 2000, enough to keep the shifting to a minimum while allowing me to be lazy and use the cruise control. With the gas engine the wind is more of an issue than with my previous diesel. With a neutral wind I would usually get around 8 3/4 mpg running this speed. With a headwind it could drop to mid 7s and with a tailwind be somewhere in the mid 9's. This is all hand measured by dividing miles covered divided by gallons used and I always use the same procedure to fuel. I typically buy Loves or Pilot/J when towing.
On the way home last week I decided to play with the speed a little and see if I could wring a little more mpg out of the truck, seeing as it had about 10k on it and was broken in. I dropped my speed to 62mph traveling up I75 through Florida into south GA. When I fueled at the new Buc ees south of Atlanta I got about 9 1/2 with a very slight crosswind. The next leg was from NE Alabama up I59 to I75 and then to Corbin KY, that part netted me 10 1/4 due to a strong tail wind from the south. After that the wind turned from the North and the mpg plummeted to around 8. My average the entire trip was right at 9 after i slowed down and around 8 3/4 running 64. My diesel never got over 11 pulling a smaller trailer so given the price of diesel vs gas I am still in the good.
I would also note that the trip odometer mpg typically came close to what I actually got. It was about 3% off to the optimistic side but very consistent. Typically if my actual showed 9.1 mpg the trip mileage would read 9.3

Scott

Great feedback Scott.

I'm not sure if Pilot is Top Tier but its important to use Top Tier fuel. We have been buying fuel from Kroger where we save a great deal with points from buying groceries there. I noticed some driveabliliy issues on the wife's XT5 and after a closer look, I found they are not top tier. Then found that Shell in our area will accept our Kroger points where the drive quality and fuel economy returned. So the point is the Top Tier designation makes a difference.
Fellows I worked with had been telling me of 18mpg non-towing on that truck a few years ago on the flat Michigan highways. When I had seen TFL filling that truck with 85 octane for their testing, I lost all trust in them.

Jim

familytruckster4 My 17 had pucks in the bed. Between the original puck system release by GM and the current system, there have been changes. I think all 3 now run the same puck pattern (which should help in the long run). I do not know exactly when GM started offering the puck system in the trucks, but I do know the 17's had them.

I only knew 2019 and 2020 because the spread is different than the 2021 and up, I learned that info the hard way. Thanks for the heads up.

Gasoline grading has been getting foggy lately. I agree on the Top tier and I typically buy fuel at Costco when I am home in part due to that and the fact that all my stuff runs well on it. The lack of any designation on the Loves pump doesnt bother me, my experience has always been good with their fuel. I trust Pilot/J less mostly because of their past financial problems but I have never had an issue.
I will however not use Speedway fuel of any kind. I got a bad tank just North of Cinci on I-75 about 7 yrs ago that cost me a tow and a new fuel filter on my Duramax. They denied my claim even though I had the receipt for 28 gallons and that was the last fuel I bought. They tried to blame it on the fuel I got in TN the day before (which coincidently ran fine and was virtually gone when I topped off) I should have sued them. Had I not had connections with the tow company, a heated garage and spare fuel filters that I could replace it would have been well over $500 if I had it towed to the local dealer.
The 85 octane seems to be a thing West of me. I noticed it on my Iowa trip last summer. TFL is pretty solid and they didnt try to obscure it so I give them a pass.
Funny story about Andre and Mr Truck. I met them at the Silverado reveal in Detroit for the new 2019 model. At the time I didnt know exactly who they were. All the local Tv stations were there and I even got my mug on the news. I came home and was talking to my son who told me who they were. I was disappointed that I didnt get to chat them up. Mr Truck got yelled at for crawling under the diesel truck trying to confirm it was the diesel and where the DEF tank was, they hadnt yet released any info on the 3.0 and this was clearly a prototype.

Using 85 octane when they used 87 on another brand is not acceptable. These engines are sensitive to having the correct octane where once they begin knocking (can be inaudible) spark advance gets pulled and torque falls off significantly. 85 is common out west but trucks that specify 87 or 89 or even premium should be filled with the proper fuel since the best torque will be achieved.

I've spent countless hours on Eisenhower pass as well as Loveland pass and miss CO.

Jim