Looks like a chain drive
I wonder why they are smiling?
Smith Form-A Truck conversion or one like it.
Is he stuck or broke down? Looks like he is holding something. The hood is off so are they repairing a roller? Scott
The worst day spent out doing something like this is better than the best day spent at "the mall", a cubefarm, Costco, or living the "suburban dream".
It is no wonder they are all smiles. They have life by the tail, and they know it !
He's holding "lunch".
He's having some of Mama's cornbread. No wonder he's smiling!
Looks like he has somebody in a potato sack in the back of the bed. Probably the mother in law..
Probably not cornbread since they are in Western Pennsylvania...zucchini bread maybe.
I lean toward a "plug" of tobacco. They are not "stuck" They are just resting, They found a "good section" of road and decided to stop for a "chew" Back then, the boy probably also had a "chew".
Are you sure it's not his cell phone calling for help?