I have determined the nearest Peterbilt, grey and black stripe, to be a 359.

Considering there is just walking room between the trucks, to my eye, the near truck stands head and ears taller than the other two Peterbilts.

The windshield is quite a bit taller.

The top of the hood looks to be farther from the ground.

Note how much more clearance is between the fenders and tires.

The other two Peterbilts do have the external breather tubes and scalloped hood like the 359; but, I believe them to be a different, shorter statured model.

The grilles even look shorter.

Any ideas ?

On another note:  That is Renfro Valley; notice how muddy the tires are on everything.

I have a longer distance shot of these same trucks and the foreground is full of big deep muddy ruts with water standing in them.

They have had events in that swamp for years and I have been to many of them; everything from rat killings to tent meetings; once you get past those girls with the nail aprons, you are on your own as to whether you ever hit hard ground again.

Many times, I have been there when they were log-chaining everyone in and out of the vast parking lot swamp with big tractors; and, many times I have came back to find my windshield and the sides of my truck spattered with mud from countless people spinning and slinging mud, trying to get in or out.

Once in a while, someone less experienced in such adverse conditions will fishtail into someone else's vehicle and it is always a horrendous fender-smashing crash.

You always get to see people on their knees, straining against the bumper of a spinning vehicle, while they are getting covered in mud.

In wet times, I have actually allowed discretion to be the better part of valor and vetoed leaving the house, foregoing an always looked forward to once-a-year hate-to-miss event on account of the fear of being out of sight and sound of my vehicle when someone slams into it.

Also, gum boots are strongly recommended; it is always funny to see these spike-heeled lipstick queens trying to navigate the muddy ground; you see a lot of muddy-legged gals carrying their stilletos by the straps.

Big blue crawdaddies everywhere and the stench of years of rotting food and vegetation hangs heavily in the air; when you first get there, it is plumb overwhelming nauseous; but, as the day wears on, you get accustomed to it and barely smell it at all --- but you can taste it --- even bust-your-teeth ice-cold drinks from the cooler will taste like it.

On the way back home, when you stop at a good sit-down restaurant where they bring you a menu and treat you like a human and don't take your money when you first walk in the door, you can't smell it on you, but be assured the other patrons can.

Thanks for reading.

That was my determination.

Although it would be better to have a side view, to my eye, it looks like the rear edge of the wheel-well on that first truck is ahead of the breather; whereas, on the other two, it appears it is well under the breather. 

Yes; that's what jumped out at me and made me curious to know the reasons why.

I know it is an angling shot; but, those trucks were sitting close against each other; and, I don't think it is an optical illusion.

For myself, I still prefer the late 50s early 60s Acar DC series lead in the line.  Probably a 190 or 220 cummins or even a 6L71 detroit