look closely behind the cab theres two black STACKS. and i prefer it to be close to stock appearance, known as a sleeper
its a 5.9 common rail cummins, the turbo is a S400,
Decent sized turbo lol. I just had a quick look at the comp map, you should make 600 odd on around 15psi, plenty of headroom for more boost! 30psi should get to around 800hp!