The front has a fake air intake that looks like it could have come from a jet, and of course at the back, to paraphrase Colonel Kurtz, "the fins, the fins"
I also read that the fins were based on the fins of a P 38 Lightning that Earl had seen for the first time many years ago and was so impressed he waited 10 years to replicate them (almost) in the leSabre. Squint and you can seee them.