The final and definitive Cascavel 4 and 5 (Rattlesnake) included a new engine options (by Detroit Diesel and Mercedes-Benz) and the addition of a central tire inflation system and disk brakes (instead of drums as on the Cascavel 3). The Cascavel 4 and 5 also included a commander's cupola with a new machine gun mount on the ET-90-2 turret. The option of a laser rangefinder for the main gun was also available.  The EE-9 shares many parts and components with other ENGESA products: the EE-3 Jararaca Scout Car and EE-11 Urutu APC which lowers costs and eases maintenance problems.

Total production of all Cascavel versions (Marks 1-5) reached 1,738 units built.  They are divided as follows: Bolivia (24), Brazil (409), Chad (? captured from Libya), Chile (106), Colombia (128), Cyprus (124), Equador (32), Gabon (12), Iraq (364), Iran (? captured from Iraq), Libya (400), Paraguay (28), Qatar (20), Suriname (6), Togo (10), Uruguay (15), and Zimbabwe (90).