400 m, Men
| Competition | 1978 South American Athletics U18 Championships |
|---|---|
| Venue |
Montevideo
 URU
|
| Held | — |
| Status | Medal |
| Competitors | 3 |
| Countries | 3 |
| Pos | Athlete(s) | Country | Mark | ||
|---|---|---|---|---|---|
| 🥇 | Joaquim Cruz |  BRA |
50.15 | ||
| 🥈 | Sergio Cárdenas |  CHI |
51.69 | ||
| 🥉 | Moisés Del Castillo |  PER |
51.82 |