the "engine" itself is certainly capable of producing 507HP. i think de-tuned is the wrong term. manufacturers typically don't reduce HP on purpose. it is the result of external factors. when swapping a large engine into a small body (Chassis), there are restrictions on the intake and exhaust sides of the engine. intakes plenums and exhaust headers may have to be configured differently to accomodate the smaller space in the engine bay. as a result the intake and exhaust sides of the engine see more restiction and as a result make less HP. you also need to look at other things such as exhaust routing (Again more restirctive) and the catalytic converter(s), they maybe reduced in number or size (Remember smaller car with less room). All of these things will contribute to reduced HP.
