aircraftspruce.com will have the foam you want if you can not find it. Also check http://www.fiberglassspecialtiesinc.com/ for glass stuff. There are others too. I get the model foam from my lumber yard but order foam for my full scale bird from aircraft spruce. They are good. You can get it in blocks that will do what you want. An 8 x 16 x 32 block is about $30 in the catalog I have, but it is a couple years old. Check them out on line. Might be more than you want to spend on foam.