1966 to 1977. One generation, one body style, one platform. Small enough to be nimble, tough enough to work, simple enough to be serviceable anywhere. When Ford redesigned it in 1978 they made it bigger and softer. The original was better.
We know the early Bronco's weak points intimately. Floor pans, cowl, inner fenders, cab corners — the specific places rust finds these vehicles first. Every Bronco that leaves this shop has been driven before the customer sees it.