This direct fit bolt on upgraded HPOP is perfect for mild to moderately upgraded engines. The stock output Heavy Duty version has all the same upgrades as the high output version in regards to durability. This option is for stock injectors up through 190cc. It is a perfect option for those not looking for High performance parts as the longevity - in theory - might prove better on these units as one would presume. The DieselSite "Stock Output" Adrenaline HPOP is slightly larger in volume than a stock pump.