You need more gear and compression for a 500hp 454 in a heavy truck.
The cam you have is already too much for a 2.73 gear and compression in the mid 7's. And tall tires will make that worst. Plus a higher stall converter will be needed.
If you don't plan to increase compression, add more gear and higher stall, then add boost to make your HP goals. And use a smaller cam that matches the gear and stall.