With the lifters, tie-bars, and guide retainer installed, we can now get everything set to put in the Patriot Performance Freedom Series heads. First, the block's deck must be thoroughly cleared of any imperfections so the head will firmly seal against the block. Then we add the head gaskets. Most head gaskets are marked "front" so they can't be installed backwards. Notice the two locating dowels at the front lower and rear lower head bolt holes. Sometimes when removing the stock heads, these pins stay in. Make sure they're in the block when the new ones are installed. They'll make it easier to set the heads in place.
While the timing chain cover is installed, Chris torques the heads to spec. There are several different lines of thought when it comes to the torque specs. When torquing the heads, begin from the two center bolts and work out on each side. Move to the right, then back to the bolts on the left of the center two bolts, then torque the outer bolts in the same sequence. The recommended torque specs are 70 lb-ft for top and bottom, but begin at around 45 lb-ft and progressively work up to 70 lb-ft on each bolt.
Aftermarket roller rockers offer greater valvetrain stability compared to factory stamped steel rockers. The stamped steel rockers are known for flexing under heavy loads, and you don't want that at high rpm. Working with individual cylinders, rotate the engine using the crank damper bolt until each valve is closed. The rocker's corresponding lifter is riding on the camshaft's base circle, not on the lobe, meaning the valve will be closed and fully seated. Tighten the rocker while turning the pushrod with your fingers. When you can no longer turn the pushrod, the lifters are preloaded. Tighten the poly lock on the rocker and repeat the procedure on others. If you're confused by this at all, it's best to have someone with roller rocker installation experience around.
With the valvetrain set, Chris moves on to ready the engine for the Cobra intake. He uses a threaded rod to put the gaskets in place, and he puts RTV silicone around the water passages for further sealing capabilities. The threaded rod not only keeps the gaskets in place, but they'll help us immediately align the intake in the right spot.
As he did in high school, Chris uses a cheat sheet to help him with the intake torque sequence. Just as the heads are torqued in sequence, the intake has a special torque pattern and specs, which are more involved, requiring a caption the size of the NFL's substance-abuse policy. We don't have that many pages, so consult a Haynes or Chilton's manual for the sequence.
Similar to many other head/cam/intake stories we've done, the stock valve covers wouldn't clear the aftermarket roller rockers. Since it was getting late in the day, we used a pair of sheetmetal valve covers, which not only clear the rockers, they look great doing it. You can also see we've reinstalled the fuel injector harness, and much of the front accessory drive system. We didn't break open the A/C system for this operation, either. We moved the compressor and lines out of the way to gain access to the engine.
Before adding the Cobra upper intake, we checked any clearance issues with the sheetmetal valve covers. With just a gasket between the upper and lower, the valve covers would contact the throttle cable so we had to use a spacer to make everything fit.
Make sure all cables, electrical wires, and harnesses are out of the way so you can lower the upper intake into place. Locating studs aren't necessary for installing the upper intake, but if you choose to use them, only do so in the passenger side front and rear-most bolt holes. If you have someone helping you install the upper, you most likely won't need any locating studs in order to install it in a timely manner. Don't tighten all the bolts until they're safely threaded into the lower.
Moving underneath, it's time to add the BBK long-tube headers. These headers were on the car prior to the dyno-testing, but stock exhaust manifolds were put on the car for our baseline numbers. In order to install the headers, we had to loosen the motor mounts and jack up the engine. While one person is feeding each header up from the bottom, someone else needs to be up top to thread in the front- and rear-most header bolts to prepare everything for the header gaskets.
We've tightened the motor mounts, installed the headers and H-pipe, added new spark plugs to the Patriot Performance heads, and reinstalled the distributor and spark plug wires. All that's left to do is reinstall the air intake system, add fluids, and throw the car back on the dyno to reward our hard work with increased horsepower. Here, Chris is installing the stock intake tube, mass air meter, and a K&N conical filter. We didn't quite reach our 300hp mark with the stock air intake setup, so after we left, Chris fitted the car with a JLT Performance cold-air kit, a C&L Performance 73mm mass air meter, and a 70mm throttle body.