My take on this is it was more than likely a V8 car with no title so they put the fender tag and riveted a VIN tag from a \6 car they had a title for. I would almost bet if you drill the rivet heads off the VIN tag it would fall off.
That does not mean your V8 car is stolen it just means somewhere along the line someone did not have a title for it so they took the easy route and swapped what they had to it.
I would think the easiest way to check if this is true clean the end of the torsion bars and get those numbers. If they come back to factory V8 bars then it is probably a tag swap because just a driveline swap guys dont change the bars and usually leave the \6 bars in.
