Here are the specific materials that earned the "fuerte" (strong) designation in engineering catalogs and technical papers from that year.
In 1986, the best carbon fibers (like Toray T800 or Hexcel IM7) offered a tensile strength of over 5.5 GPa (gigapascals) with a density of just 1.8 g/cm³. To put that in perspective, that is five times stronger than 4340 steel, but four times lighter. materiales fuertes 1986