I'm 6 foot 7, whats the best truck for me?

Nah...gotta have 2-stacks.

 

Have you scaled the tractor?

 

Other tall dude here at 6'9", put your coolness factor aside, forget the brand of trucks you like or are attracted to and go the truck dealers and sit in all of them.

Find the trucks that are most comfortable for you to drive.
Sometimes you find that the truck with the most room is not the most comfortable to drive.
Check out seats and seat options, cushion width and depth can be a deal breaker when it comes to legroom and comfort, a thinner back cushion will let you slide the seat back a little further in a truck without an integrated sleeper, an inch is an inch.

Being tall you are more prone to back injury and it might be better to find a seat that fits you first then buy a truck that fits you and the seat, you may need longer/wider cushions to fit your body.
Being as tall as you are nothing is built to fit you and if it is it cost twice as much.

Observe the steering wheel in relation to the seat, is it centred or right of centre, check the size of the steering columns, smaller is better.
Leg and head room are what you are looking for, stacks and doodads should be an afterthought.
Being a big dude, you don't want to be sitting on the floor like in a go cart with your knees on either side of your head or knees banging against the dash.

 

Just get a truck. When you own the truck, unbolt the seat and drill new holes so the seat will go back another two inches. Unless your driving a day cab. If your driving a day cab you will need to make the seat back thinner so you can get your tail back more.

Otherwise go to a dealer (if buying new). Ask them to let you sit in their cabs. Tho I think your killing your options limiting yourself to only two truck manufacturers.

 

More like what was my truck, retired now.
I was pretty comfortable driving an IH 9370/9400/9900, also KW W900's and T600's with integrated sleepers, these were probably my favourites, especially if they had a sunroof.
(liked the cool night breeze in the cab that didn't mess my hair)

Drove a new Volvo 780 from time to time for a friend, wasn't too thrilled by it.
Sat in a few WS's, seemed roomy enough.
Have only driven one Pete, for a week when a friend was on vacation, an old 359 day cab, not a contender.
I have a personal hate on for FL's that goes back nearly 40 years, but don't let that stop you from looking at them.

Have no clues how roomy the modern cabs are which is why I urge you to go sit in all of them.
That's what I would do if I was in your situation, comfort and health comes first, the brand of truck, the driveline and the truck's appointments come after.

I've had back surgery, much to do with trucks that rode rough and didn't fit me well, and I'm pretty sure you want to avoid the pain, suffering and down time at all cost.

 

I have an international and 2 kw's, When I stayed on the road and stayed in a truck, I drove the binder,
I cant imagine any W9 or T800 having as much room.

When it comes to your legs hurting, there is more to it than room. A seat good seat is very important to me, I am talking VERY, and just because it is a high dollar brand, doesn't mean it is worththy of riding on the dromdeck.
Another important deal for your legs, is the way the pedals are and the angle your foot sits on the throttle pedal, which is different between brands.
I have driven everything from old cabovers and b model macks to most newer trucks on the road, and was born with a bad back, I have found these two things the most important, when they aren't good, my legs have gotten so painful that I have literally had to shut down because of it and I have a high tolerance for pain.

Somebody mentioned liking a sunroof in them. My W9 has one and for the life of me, I will never figure out why anybody would want one in a truck, Now the company that built the sunroofs, no longer dows, NOBODY makes a replacement, Kenworths solution if yours breaks, is to put a new roof cap on it. lol

 

Internationals pivot off the floor. I prefer Freightliners as all the pedals swing from the firewall like cars do. It is just me. The other thing about freightliners is that parts are more readily available with Freightliner. Most megas run Freightliners. So add that to what you intend to get. Availability. Yet freightliners are often given bad rep by drivers whom dont like the quirks of their higher miles. Tho the quirks are easily solved if your the owner. One quirk is the doors let the wind howl which is usually a requirement of a new door gasket and get the door striker adjusted (about $100 cost parts). The other quirk is the windshield leaks. Generally if it leaks the rubber gasket needs replacing.

Freightliners generally have a split windshield. Yet the split is over on the shoulder so it doesnt really affect your ability to see. The nice part is, if you have a broken window? Your only replacing half of it as opposed to all of it.

The other thing is to ask this question in the owner operator area of the forum.
https://www.thetruckersreport.com/truckingindustryforum/forums/ask-an-owner-operator
There you will get the actual owners. Title it question about seats. Or use what ever you want.

A college isntructor once told the class a sage bit of wisdom.
There are no dumb questions. The only dumb question is the one that is never asked. Always ask a question and become better informed.