'a delivery van' is correct and can be used in written English.
You could use it in a phrase like 'The delivery van arrived late due to traffic'.
Across the road a delivery van drew up.
Further uptown on Eighth Avenue, a crowd stood around a delivery van, listening to radio reports.
Once, he posed as a delivery van driver to contact her at work.
There were no cars, just one lorry, a delivery van and a few tractors.
Eight machines, the biggest the size of a delivery van, are busy making things.
The reservist had made a significant investment for a route and a delivery van, according to the article.
In swerving to try to avoid the bicycle, the woman ended up hitting a delivery truck, a second delivery van and then a parked Nissan Maxima, witnesses said.
A male classmate stood with her until she got a ride from a man in a bakery delivery van But once under way, she recounted, "He said I must go to town with him".
The "ambulance" waiting downstairs was a makeshift delivery van with a wooden plank for a bed.
"A few years ago a large delivery van turned up on campus with a brand-new fridge-freezer.
The jihad by Muslim extremists against the West began at 1 05 P.M. on April 18 , 1983 when a dark delivery van made a sharp left turn onto the cobblestone drive of the U.S. Embassy in Beirut.
