Remove the three 10mm cam gear bolts. Pull off the top pulley and remove the timing chain from the cam gear. Install a water pump bolt in the end of the cam and spin the camshaft until all of the lifters have been pushed up into the lifter trays. Check each pushrod to see if it is in the “up” position. Very rarely will a lifter fail to seat itself in the tray but if it does, the intake manifold will have to come off to get the stray lifter out of the path of the camshaft. Pull each of the pushrods out and store them. Remove the four 10mm cam retainer bolts.
After attempting to remove the cam, it was determined that the lower valance panel that is retained with five 7mm bolts would have to be removed. Removing this allowed the condenser to be pushed toward the front of the vehicle, allowing sufficient clearance to remove the cam. Wash the new COMP Cams camshaft in soap and warm water. Allow to dry and then lubricate all journals with motor oil. Attach a water pump bolt to the front of the camshaft and carefully guide the camshaft into the engine block. Go slow and stay straight, as you do not want to nick a camshaft bearing by being sloppy.
Install the camshaft retainer and torque the retainer bolts to 18 lb-ft.
Stretch the chain over the crankshaft and camshaft sprockets. Put the cam gear into the proper position on the camshaft sprocket-locating pin, in the sprocket alignment hole. Make sure that the camshaft sprocket alignment mark is in the 6 o’clock position. If necessary, rotate the camshaft or crankshaft sprockets to align the timing marks. Put blue Loctite on the three cam gear bolts and torque the cam gear bolts to 23 lb-ft. Reinstall the cam tensioner and torque the bolts to 18 lb-ft. After completing the camshaft installation, reinstall the oil pump and torque the bolts to 18 lb-ft. Raise the car in the air and torque the oil pan bolts to 18 lb-ft and the two bellhousing bolts to 37 lb-ft.
The valvesprings will be removed using a HPE-designed LS series in-car valvespring removal tool. Rather than pulling the heads to change the springs, the tool in combination with a special air fitting that threads into the spark plug hole, will keep the valves from falling down onto the pistons once the air line is pressurized and the valvespring is removed. The tool accepts a 3/8-inch socket fitting on both sides to provide tool leverage to compress the spring. Not included with the tool but necessary to change the springs are a 1/2-inch breaker bar with 3/8-inch socket, the air fitting and two long rocker bolts. After screwing the special spark plug fitting into cylinder number two, an air hose is attached, pressuring the cylinder to 120 psi. Put the valvespring tool down onto the valvespring that will be removed and then secure the rocker bolt with an 8mm socket. Attach the breaker bar and 3/8-inch socket to the side of the tool and position a magnet near the center of the valve retainer. Press down on the breaker bar and carefully compress the valvespring until the locks are free of the retainer and extract the locks with a magnet. If the valve stem moves down with the spring retainer, tap the retainer lightly until it moves independent of the valve.
Once the locks are removed, carefully lift up on the breaker bar until there is enough clearance to remove the spring, retainer and machined bases. To remove the intake and exhaust seals, pull up on them with a set of pliers until they clear the valve stem. Before installing the new Viton valve seal, remove the factory-machined base and replace it with the Patriot-machined base. Lubricate the valve stem with a couple of drops of oil, slip the seal over the valve stem and then use a deep 8mm socket and hammer to tap the seal until it comes in contact with the valve seat (machined base). Place the new Patriot Performance double springs over the valve and then place the titanium retainer on top of the spring. Use a small dab of grease and install the two new Super 7 valve locks into the top of the retainer. Compress the valvespring tool until the valve stem protrudes past the retainer enough for the two valve locks to fall into place. The locks fit into grooves on the end tip of the valve stem and positively locate once inserted properly. Once the locks are secured, reduce the pressure on the valvespring tool until the spring is seated. Place the tool on the cylinder’s intake valve. In addition, on the LS7 the offset intake rockers require a lash cap, so remove it and don’t forget to reinstall it with the new valvesprings. Once complete with both valves on a cylinder, repeat the process for the remaining cylinders.
The 16 COMP Cams pushrods are inserted into the access holes in the cylinder heads and the stock GM 1.80 ratio roller rocker arms are reinstalled and blue Loctite is placed on each of the rocker bolts before the rockers are torqued down to the factory spec of 22 lb-ft. After making sure no foreign debris has fallen into the head, install the valve covers and secure the 8mm bolts by torquing them down to 9 lb-ft.
Before starting to reinstall the suspension, belts and radiator components, raise the car and slip the driver side header up and into the engine compartment. Once verified the header will fit, apply some anti-seize to the threads of the front O2 sensor, install the O2 sensor extension and tighten the sensor down with a 7/8-inch wrench. Slip the header back into place and put a single 13mm bolt in the back head bolthole to hold the header in place.
Move over to the passenger side and trial fit that header. Unfortunately, the dry sump oiling system lines are in the way and will have to be removed in order to install the header. Place an oil drain bucket under the lines and use a 13mm wrench to remove the lines.
Slip the passenger side header into position and then install the O2 sensor extension and O2 sensor. Slip a single bolt into the rear header bolt. Lower the car and prepare to install the factory exhaust manifold bolts. After cleaning the bolts up with a wire wheel, coat the threads with anti-seize compound. Inspect the exhaust manifold gaskets for any imperfections and if none are found, reuse them. Remove the rear bolt and slip the exhaust manifold gasket in along the head until it slides into the groove for the rear bolt. Position the gasket and thread in the rear bolt (with lock washer), followed by the four remaining bolts. Tighten each of the bolts up in increments, starting with the centers, working your way outward. Once each of the bolts is snug up against the header, torque the bolts to 18 lb-ft, or “very snug” with your 13mm wrench. Don’t over tighten and strip the aluminum threads out of the cylinder heads. Install the passenger side header in a similar fashion. Install the plugs on the passenger side, followed by the valve covers, coil packs and plug wires. Move over to the driver side and install the steering knuckle, followed by the plugs, valve covers, coil packs and plug wires. Reinstall the fuel line, throttle body, PCV connections, fuel rail covers and radiator components before moving under the car to install the Kooks mid-pipe.
The rear O2 sensors are removed from the factory H-pipe and transferred over to the Kooks mid-pipe. Use anti-seize compound on the threads and tighten the sensors with a 7/8-inch wrench. The Kooks mid-pipe is then bolted to the 3-inch header collector with two studs utilizing 15mm nuts and flat washers.
After tightening the collector junction, locate the two 13mm nuts that you removed earlier from the mid-pipe retainer brackets, and hang the mid-pipe back up. Move to the rear of the mid-pipe and slip the cat-back exhaust and mid-pipe together. Tighten down the 15mm nut on the Accu-seal clamp on each side. The factory mid-pipe is 3 inches in diameter and features an integral H-pipe. When combined with the hydro-formed tubular stainless steel exhaust manifold and catalytic converters, it flows better than any Corvette to date. Although improving on the exhaust flow is difficult, the Kooks system helps scavenge additional exhaust, allowing the LS7 to generate more power.
Key Engine Parameters: Maximum values noted, *unless otherwise noted