The duo, in a team also including last year's IRL champion Tony Kanaan, won the 12-hour race despite qualifying fifth. It is Sao Paulo-native Barrichello's second 500 mile win on the trot.
Honda-bound Rubens Barrichello, 33, has now won the 'Granja Viana 500' six times.
The young man who is replacing him at Ferrari, countryman Felipe Massa, qualified on pole – nearly a second clear of Rubens' team – for the 600-lap event, and were the quickest team all weekend.
Marco Andretti crashed in the rain and was taken to the local hospital for a checkup but was pronounced OK.
Elsewhere in the motor racing world, Lucas di Grassi won the prestigious Macau F3 grand prix from Robert Kubica, with Sebastian Vettel third.
In the US, 2002 champion Tony Stewart secured the 'NASCAR Nextel Cup' at the Miami finale, while France – this time with Alexandre Premat at the wheel – continued to dominate the 'A1' series with another double victory at Sepang.
Granja Viana 500 – Top-10 finishers:
1) Rubens Barrichello-Tony Kanaan-Felipe Giaffone-Dan Wheldon, 615 laps
2) Vitor Meira-Juliano Moro-Pedro Pimenta-Beto Nini, 613
3) César Ramos-JÃºlio Reis-Pedro Gomes-Roberto Gomes-Fernando Wortmann, 607
4) Felipe Massa-Rafael Daniel-Ruben Carrapatoso-JoÃ£o Paulo Bertuccelli, 606
5) Rubens Barrichello-Tony Kanaan-Marco Andretti-Alexandre Barros, 605
6) Osvaldo Badula-MÃ¡rio Maia-Geraldo PavÃ£o-AntÃ´nio Urbano-Paulo Leme-MarÃ§al Mello-David Prior, 605
7) Jorge Borelli-Vinicius Quadro-George Altmann-Felipe Ferreira, 605
8) Dennis Dirani-Daniel Landi-Rafael Monteiro, 605
9) Christian Fittipaldi-MÃ¡rio Haberfeld, 602
10) JoÃ£o Paulo Bertuccelli-Marcos Gomes-PopÃ³ Bueno, 599