When I hear "stock" I think the car is 1.) either as delivered from the factory (Factory Stock) or 2.) Modified using parts that all have a OEM part number (All the parts come from Dealer Stock). Scat Pack Packages have a Mopar part number and come from Dealer Stock. Putting a Hellcat air box on a non Hellcat car is using Dealer Stock parts, same with the old "Purple Shaft" cam shafts or putting a LSD differential from a Scat Pack in an R/T, is using Stock Parts.
To me, using OEM parts, either factory replacement or Performance based is preferable to non OEM parts, I just wish they weren't so damn expensive and I wish my local dealers could tune cars.
In my next life, I am going to open a Dealership and offer in house dyno tuning......
Right never opened the engine....and if it's a supercharger or turbo and or pro charger without porting heads a TC and or not having did anything but the simple stuff.....what's the chances of a classic running low 12s without going into the motor
Stock, is no performance part changes have been made. Even swapping from other vehicles if different, it is not stock. There are other ways to drill down into it (stock engine, stock bodied...), but if you are comparing one car's times to another and 1 has zero changes, and one has different mufflers, or intake anything, or cam, or gearing, or NOS, or anything that was not a factory accessory/option for that year and exact model, it is not stock.
It comes down to personal preference or opinion at the end of the day. Personally, when I think stock, I think of 'stock' as when a car or engine is completely unchanged or altered (aside from general maintenance i.e. oil filters, etc). While it can be argued that stock would also apply for a car that has had after-sale OEM parts that could be ordered added to the car, this is still classified as modifications. Essentially, if it differs from the build sheet/ window sticker, it is not stock.
Yes, stock has always meant unmodified, period. And it's still what it means to me. But in these fastest stock xxxx videos, they are saying not been into the engine. There could be an eight liter blower on top, and if the stock internals survived, it's the fastest stock xxxx to them.
I believe that is what the OP is asking about.
To me if you add drag radials, you no longer have a stock xxxx. You have an xxxx with drag radials. Stock would mean a car that was manufactured that way at the factory or upfitter, before delivered to the customer. if you add parts that are available from the manufacturer, but weren't originally installed before delivery, it's not stock IMHO.