The idea being that if you're going to make a dragstrip gasser out of a pickup, you'll need to put a bit of extra weight over the rear end to improve traction. Otherwise, you'll just be spinning the tires at go. Hay bales push the tires down onto the tarmac, which translates into a better quarter mile.
15x25 inches, watercolor. Available for purchase here.
p.s. I'm currently working on Ballast 2, featuring a mid-60's Dodge truck.