Revealing mistake: When Steve and Jonathan are climbing the radio tower, just before they reach the top, there is a wide shot, and if you look at Steve, you can see the far background around his body is swirling, revealing the shot to have been filmed in front of a green screen. (00:20:32)
Factual error: Holly is wearing Under Armour when she is escaping from the upside down. Under Armour was created a decade later.
Answer: They're both muscle cars, but that's about the extent of the similarities. But the 70's were filled with a lot of muscle cars, so some car models may look a bit like another's. Billy's car is a late 70's Chevy Camaro (probably a ‘79). Mad Max's car is a 1973 Ford Falcon XB GT. Incidentally, the Ford Falcon was produced by Ford Australia and wasn't an American car, or even sold in America (as in not sold at dealerships).
Bishop73
According to the experts its a Camaro '78 with added vented side fenders.