Intereted in buying a truck with a N14 Cummins 370hp engine in it How far can this engine be turned up or are you limited to 370hp?

Intereted in buying a truck with a N14 Cummins 370hp engine in it How far can this engine be turned up or are you limited to 370hp?
Does it have mechanical fuel injection or the new electronic injection. what transmission do you have ? why do you want to turn it up ?