These lines are to replace the typical high mileage expensive leaky OEM HPOP lines that have the STC fittings. Kit comes with passenger, driver, and crossover hoses along with all necessary fittings to eliminate the quick connect fittings (STC) on the heads and the HPOP itself. All new Genuine Brennan™ fittings DuPont Teflon™ lining just like OEM Burst pressure rating of 16,000psi Working temperature rating of 400*F Nominal working pressure is 5000psi High quality Viton™ o-rings MADE IN THE USA IN OUR SHOP The HPx line connects the two heads to help balance the high pressure oil system in each head. It does not create more horsepower, but the majority of owners see a slight to significant decrease in engine idle noise. This is due to the Helmholtz resonance that is created from the injectors firing so quickly, and the HPOP cannot react quick enough to balance/absorb on its own from back pressure spikes within the system. So when the tiny spikes happen, the HPx line sends the pressure back and forth through the heads instead of hammering on the pump itself. INSTALLATION: Disconnect the battery grounds before installation to avoid accidentally arc'ing the line on the glow plug relay or the alternator charging lug. Use pictures from the product webpage for routing example. The fittings are marked with numbers to match installation location (see below for reference). After installation, be sure there are no other lines/wires that are touching the lines that could potentially rub through and damage either the HPOP line or the other line that may be touching it. Use a small section of wire loom protector or a larger piece or rubber hose to wrap around the contact point. Many will remove or bend the engine eyelet on the driver side as a precaution, but it is not necessary. Sealant is not necessary, but IF you choose to use any, use Loctite 680 or Permatex 64000 retaining compound (green) only on the fittings installed in the HPOP. If you are unsure of installing yourself, seek out a competent and qualified technician to install the lines. *REMOVE THE SPRING CHECKS IN THE PUMP UNDER THE STOCK FITTINGS, DO NOT RE-INSTALL* HOSE IDENTIFICATION: 98.5-03 2 LINE-BOTH SIDES ARE SAME LENGTH. 94.5-97 2 LINE- PASSENGER IS LONGER OF THE 2. **FOR ANY 3 LINE KIT THE SHORTEST LINE IS THE CROSSOVER HOSE. FITTING MARKINGS: 1- FRONT PUMP PORT 2- REAR PUMP PORT 3- DRIVER HEAD 4- 94.5-97 PASSENGER HEAD 5- 98.5-03 PASSENGER HEAD AND CROSSOVER **94.5-97 driver side fitting gets moved forward one port on the head to match 98.5-03** Pump Fittings: 28FT/LBS • Head Fittings: 23FT/LBS • Hose Ends: 21FT/LBS