To obtain the clearance necessary...
To obtain the clearance necessary to slide the Y-pipe out from the header junction, the aftermarket Spohn adjustable torque arm needs to be loosened. The four 12mm bolts that retain the torque arm to the body are removed.
In addition to the heads, Jason strongly recommended that the small 26.4-pound factory injectors be upgraded to a larger set of FAST 42-pound injectors (PN 304208, retail $372.33) to ensure the engine would be adequately fueled with the upgraded heads.
Before heading off to install the PRC cylinder heads, let's summarize the combination currently installed in Harold Baker's automatic '00 WS6 T/A. Sporting 66,500 miles, the Bird has an SLP LS6 intake manifold, Jet-Hot headers, an off-road Y-pipe and a Comp Cams hydraulic roller cam with a Comp dual valvespring kit and Hi-Tech pushrods. Real Performance Motorsports (RPM) in Lewisville, Texas, performed the installation and expertly tuned the T/A. In addition to the components from the "LS1 Power Plan" (Aug.-Sept. '08), the car has a long list of free mods and cost-effective mods, including a Corsa after-cat exhaust, BBK 80mm throttle body and an aftermarket suspension.
The torque arm is pulled down...
The torque arm is pulled down on the passenger side and the Y-pipe is simultaneously tapped backward until it separates from the headers. In this case, the header to Y-pipe junction was so tight that the Y-pipe was separated after the test tube. The Y-pipe is then twisted and wiggled loose from the junction to the after-cat and removed.
Follow along as Matt Garzonie at RPM installs the PRC cylinder heads in Part I, then in Part II completes the final assembly, including swapping out the factory injectors for the FAST injectors. Once that's done, we'll show you how the T/A performed both on RPM's Dynojet chassis dyno and in the 1/4-mile at San Antonio Raceway in Marion, Texas.
Recommended Tools & Supplies
- Die-grinder (air-powered, low rpm)
- Flat-blade screwdriver
- Fuel line disconnect tool
- Grease and wax remover
- LS-series in-car valvespring tool
- Metric socket set
- Metric wrenches
- Razor blades
- Standard wrenches
- Torque angle gauge (J-366660-A) or equivalent
- Torque wrench
Once the front mount bolts...
Once the front mount bolts came loose, there still wasn't enough room to pull down on the torque arm mount and slide out the Y-pipe, so additional clearance was gained by removing the factory aluminum driveshaft. This is accomplished by pulling the four 11mm U-joint bolts, then removing the Spohn safety loop on each side (two 12mm bolts each).
The intake manifold and all...
The intake manifold and all accessories attached to the cylinder heads need to be removed as well. After lowering the car and unbolting the aftermarket strut-tower brace, the intake manifold is next. The fuel line is liberated from the fuel rail with a fuel-line disconnect tool, then the various sensors including the intake air temperature (IAT), mass airflow (MAF), idle air control (IAC), throttle position (TPS), and PCV valve are disconnected from the throttle body.
The EGR valve wiring harness...
The EGR valve wiring harness is unplugged and the two 10mm bolts that retain it to a cylinder head-mounted bracket are removed, followed by the intake manifold ground strap. Throttle and cruise control cables are disconnected and the SLP LS6 EGR pipe is removed from the intake manifold. After the wiring loom is detached on both sides of the manifold, the eight fuel injection connectors are slipped off. The manifold is retained by 10 8mm intake manifold bolts and once they're loose, the wires and connections are moved to the outside of the manifold to ensure they won't impede manifold removal.
The power brake booster connection...
The power brake booster connection is pulled off at the brake booster and the four rear manifold bolts are lifted up. Then the manifold is gently lifted upward and forward approximately 6 inches to allow access to the manifold absolute pressure (MAP) sensor and the vacuum line sitting alongside it. After disconnecting them, the manifold is moved forward, paying careful attention to the brake booster hose as it will need to be guided out in order for the manifold to be removed from the engine.
The EGR tube on the passenger-side...
The EGR tube on the passenger-side header and the AIR tubes on both headers are removed with a 10mm socket, along with the dipstick tube (single 15mm bolt to head). Plug wires are then disconnected from the coil packs along with the coil pack harness connections. The pack is taken off by pulling the five small 10mm bolts that attach it to the valve rocker cover. Four valve rocker cover bolts are then removed with an 8mm socket, allowing full access to the pedestal-mounted 1.7-ratio rocker arms. An 8mm swivel socket on an air ratchet quickly loosens all the bolts. The process is repeated on the passenger side, then the pedestal rail and rocker arms are taken off as a unit and the assemblies are stored in cylinder and bank-specific order.
After sliding out the Comp...
After sliding out the Comp Hi-Tech pushrods, the ground wire on the back of the driver-side cylinder head is taken off with a 15mm wrench, then a 10mm socket is used to remove the front coolant bypass tube and the two rear coolant block-off tubes.