How do you turn up the horsepower on an international 466?

How do you turn up the horsepower on an international 466?
Fuel injector pump will have to be recalibrated on an injector pump stand at either dealer or certified pump shop (ansi) to larger injectors. IF this is a pre-electronic or manual Bosch type pump. The I-H navistar 466 has been in service many years and several fuel delivery configurations have been used on this engine. If it a late model computerized or ccst(computer controled step time) all that may be needed is a "rewrite". A set of instructions given the E.C.M. via a diagnostic writer. Somewhat similar to "chipping" a gasoline engine.