I've had that photo for 20 years+ now, and you know what? I've never noticed that there appears to be something under the REAR tires too! Is that a scissor jack?

My guess is that they needed clearance to put headers on, or maybe to take the trans out, so they needed to raise the front and back. I never noticed that before!

Here's a another picture of the Myrtle Motors Firebird mentioned earlier, with 428 emblems.