Any old Dodge mechanics online here

Isn't the B series 'vans'
Other trucks are the D or W series

The spindle and ball joints may be different as well and may not allow the single wheel hub and rotor to be mounted. Keep looking for the right parts, they are out there somewhere.

Memories.

8.00 x 19.5" tires.

440 engine
A727 trans

One of the most stable towing platforms on the road

And best friends with a gasoline dispenser.

Old timer Dave
Do you mean Dually tires ( I think you do ) on the rear
Or
Dual = two rear axles
A third rear axle is called a tandem axle

My first motorhome was on a 72 Dodge chassis, 17" tires on all 6 wheels, front and back where the same wheel and tire,
Not positive but it might of had a Bendix design braking,, drums, shoes, and brake cylinders
I think it was a D300 chassis

Do your rear brakes have one brake cylinder at top of mounting plate
Or
Two cylinders ,
one at bottom and one at top

For each of the rear drums

They will not interchange. Maybe including the cotter pin.

Wheels are different between single rear and dually, so front hubs will be different.

That is an old truck!

Is this a D300 or a W300 truck?
My memory says they used different brands of components. Spicer was one.