Demon 340 vs Camaro 396 (400)

Yes, there are two classes under the FAST umbrella.

FAST, which is the outer appearance has to be stock, they run the repo bias ply tire, but almost anything goes internally.

Factory Stock, has very strict rules. They run the repo bias ply tire Almost as strict as the Pure Stock Muscle Car Drags. They might be identical rules, not sure, but very similar.

The confusion is understandable, by definition you should NOT be able to tell the difference between the classes just by looking at the cars.

the only way is FAST car’s number starts with F. Mine is F3400.
Factory stock I think start with S or FS, however the class is like herding cats and some guys forget to put the F in front on the number. Me being one of them.