I've had 5.5 Tigers and only the .5 one had a tunnel from another car. It was pretty obvious as it's torch job didn't match like 1.5" in most all places. Ever try to make a part bigger? It might be like the carpenters I've cut that board three times and it's still too short

but in reality it's really difficult to weld something together and then make it look like it was never a cut piece of metal with pieces added.
Lots of cars got a Sawzall hack job or worse. A real popular "there I fixed it," area is the too small area for the shift linkage adjustment, or let's cut some more holes in the firewall so you can get the transmission out with the engine in the car...