^^ +1. To see if your short block is stock, you'd have to check the pistons, crank, rods, etc. and see if it's aftermarket.
Side note: A friend of mine is going off to UTI in a couple weeks... He swapped in a twin turbo motor to his previously n/a 300zx, and is still convinced that a short block is just a motor that looks small, where a long black is larger. Is this the kind of people that will be working at dealerships in a year?
I think he was asking where he would look to see if the numbers on the block and the numbers on the head match up with the year of the car. I have no idea where to find that data.
There are casting numbers on our blocks, but the 5.0 OEM block hasn't changed for a couple of decades, I believe. The OEM GT cylinder heads were also used on the earlier models as well, if I remember correctly.
If you're trying to decide if a car has the engine changes that a seller says it has, that can be kinda rough to tell. Many sellers will lie through their teeth to sell a car, sadly. While you can tell if some parts have changed, you can't always tell everything. It is difficult to describe what to look for; can you give us more info on what you're looking for? Like, are you looking to buy a Mustang and the seller says it has XXXX parts on it? Or do you already own the car, but you think it has an aftermarket cam?
There ought to be some sort of serial number or something that would apply for a few years at least. I know all the blocks from 93'-95' are the same. 92' and older are slightly different castings.
As Kurt was saying i was trying to determine if the block and heads matched up,however its not a big deal i was just curious if there was a code or serial number to match up,but im pretty sure it is completely stock and hasnt changed at all. i own the car already and it has 96000 miles on it and bone stock other than a fluidyne radiator and k&n air filter and some magnaflows restricted by 4 cats