When Were Slabsides Invented

[msinc]

I believe it was somewhere around 64 when they came out with the fender flares on the Cobra. Cars built prior, without the flares, were referred to as "slab sides" because they looked flatter on the sides then cars with flares. IIRC the flares got even larger looking with the MKIII big block bodies. I never took it as derogatory or meant to demean the cars, just highlight an important difference. I do not believe there was any big block cars that were slab sides from the factory...if one exists it was an alteration.