All flights to Sao Paulo (GRU) have BusinessFirst. The IAH-GRU flight is currently operated by a 764 and continues to Rio de Janeiro (GIG). The EWR-GRU flight is currently operated by a 762. These flights can be upgraded for 20,000 miles each way.

To answer your question, the South American flights with BusinessFirst service (and therefore no free upgrades) are IAH-GRU/GIG, EWR-GRU, IAH-LIM, EWR-LIM, and EWR-BOG/UIO.