After pulling down different gas tanks and beating on them with drum sticks, I settled on a small tank from an early 2000's Ford Focus. It has a 10 or 12 gallon capacity. Once I got the tank back to the shop I removed the fuel pump and cleaned all the old gas out of it.
This is what the gas tank looks like still in the vehicle.
As luck would have it, two months after I bought the used tank we got one in at the shop. A 2006 Chevy Express Van was towed in because someone had drilled a hole in the gas tank to steal all the gas. The customer needed a 700 dollar new gas tank, and I got the old one. This tank was a lot larger than the one from the junkyard. It is over 5 feet long, and has a 30 gallon capacity.
These are the holes that were drilled in the tank.
The trick for both gas tank drums turned out to be the beater. When I played them with a regular felt bass drum beater they did not sound very good. They had no resonance. After trying several options I discovered that a tennis ball made an excellent beater. So I made several beaters out of old tennis balls.
Here is what the two bass drums sound like. The small drum is the washer bottle foot drum from an earlier post.