I have no idea about the snake in question (but yes, the head does look boid to me as well) but I CAN say that I have seen a very large Eastern Diamondback that was a good 6 feet long when I was first looking over my property after purchasing it. My Mom and I were deciding where we would like to put up our respective houses (it was a 10 acre piece of land that we split between us) and stumbled upon the big rattler sunning itself in a small clearing. I tell you what...we both backed away very slowly, never taking our eyes off it. We hadn't disturbed it enough for it to rattle, but another day, we came to that exact spot again and verified it's size by measuring the fallen branch and distance to the palmetto bush it was between.