400 m, Men
| Competition | 1978 South American Athletics U20 Championships |
|---|---|
| Venue |
Sao Paulo
 BRA
|
| Held | — |
| Status | Medal |
| Competitors | 3 |
| Countries | 2 |
| Pos | Athlete(s) | Country | Mark | ||
|---|---|---|---|---|---|
| 🥇 | Antônio Ferreira | BRA |
46.7 | ||
| 🥈 | Arturo Merino |  CHI |
48.2 | ||
| 🥉 | Nilton Dos Santos | BRA |
48.3 |