john; still confused help if you can, I fully understand head pressure, I gallon of water wieghs 8.3 lbs, vs 55 gallons weighing 456lbs, but if you were to put only 1 gallon in the drum, your pressures would be the same at the holes, the question would be, could an engine provide enough muffler pressure to the drum so that the amount of flow from the drum matches the bucket?