First, these are serial numbers, not VIN numbers. VIN is a standardized system that did not exist when these trucks were built.
My experience is that the Stovebolt decoder is the most accurate of those online. I don't get paid or recieve brownie points for saying so, it just seems the most complete understanding these numbers.
The next thing to be aware of is that many of the online decoders ignore big trucks like a 4400 and so far I've not seen one that would recognize a Canadian or other non-US serial number.
The other thing all these decoders do is evaluate the serial number you plug in. They can't tell if someone has swapped the cab or the number plate at some point in the past. You might look hard for evidence someone has changed something.
