That is a lot of space. For perspective, a cubic foot of foam is roughly the size of a microwave oven. You need more than seven microwaves’ worth of foam.
For a standard homeowner with standard 16 oz cans from a hardware store, you need 35 to 45 cans to fill a 55-gallon drum completely solid. how many cans of spray foam will fill a 55 gallon drum
Attach a 2-foot piece of vinyl tubing to the nozzle so you can reach the bottom of the drum. Spray from the bottom up to prevent air entrapment. That is a lot of space