Check valvespring installed heights to ensure they are equal and at the manufacturer's or machinist's recommendation. The first measurement here reveals 1.732 inch, but 1.700 inch is what Don wants. Adding a 0.030-inch shim under the spring nets a 1.702-inch height, which is close enough as plus/minus 0.010 inch is the accepted tolerance.
Run a cleaning tap through all the threaded bolt holes in each head to ensure proper clamping force and torque readings. (Do it before you install the heads to avoid getting metal shavings in the engine.)
Check piston-to-valve clearance. Apply modeling clay to the top of the piston where the valves would contact it. Add a light coat of oil to the top of the clay so it doesn't stick to the valves.
Install the rockers with the fulcrum facing the wrong direction—the flat machined surface shown on the right should be facing up, as it provides a flat surface for the locknut to tighten against.
Check for interference at the rocker and retainer as you turn the engine over. As you can see, there is no interference with these Scorpion rockers. You can also see the concave shape on the rocker (flipped over in the photo for illustration purposes) that provides clearance for the retainer. Don is using lightweight checker springs, but this procedure can be performed with the valvesprings that will be used on the engine.
Separate the intake coolant crossover from the rest of the intake on modified engines with an aftermarket manifold. It eases intake swaps and makes aligning the intake manifold with the head ports easier, since there is no worry regarding the coolant seal at the front of the manifold and timing cover.