We Build It, Small Block Chevy

Before we bolt the windage tray to the bottom of the engine, we install a protective guard so no fasteners slip and fall into the engine. To be sure none has snuck past the guard, we rotate the engine 360 degrees, listening for the rattle of nuts, bolts, or spare change. Hearing none, we attach the oil pan. It's also uniquely designed for the LS7's racebred eight-quart dry-sump oil circuit, which uses two pumps. One pressurizes oil like in every other engine, the other sucks oil out of the sump and sprays it into an aluminum storage cylinder in such a way as to separate the air bubbles from the oil. The crankcase ventilation also is run through this tank so that vaporized oil condenses out instead of being burned off, lowering oil consumption by two-thirds in racetrack conditions.

Sliding the cam into place is a delicate procedure, because the lobes are as big as will fit through the bearing journals. Four carriers holding four hydraulic roller-lifters snap easily into place. Atop each lifter, the venerable "piddle valve" is clearly visible, ready to pump lubrication to the heads via hollow pushrods.

The cylinder heads are still interchangeable left to right, as they were in 1955. They also appear interchangeable with those on the C5R race car. Ports are computer-milled, the valves stand up at a 12-degree angle (three degrees more upright than the LS2's), and the gigantic valve seats (56mm intake and 41mm exhaust) are siamesed. The titanium intake and sodium-filled exhaust valves come installed in the head, along with their titanium springs (more lightweight gear to enable that lofty 7100-rpm rev limit). We lift the feathery heads into place with ease and carefully install the five short and 10 long bolts that attach them--if any of this exotic hardware hits the floor, it must be discarded. Then a single machine torques all the bolts in the precise sequence required to properly seat the head gasket. Then we press the larger-diameter pushrods into place and install the computer-designed rocker arms. Their 1.8:1 lift ratio opens the valves 15 mm, up from the LS2's 13.3. All this enables the LS7 to ingest 100 cubic feet more air per minute than the cooking-grade Corvette can.

After a break, we install the valley cover, rocker covers, and the intake manifold, which includes most of the fuel-injection plumbing. The exhaust manifolds are engineering works of art, too. Inside what looks like an ordinary collector manifold are individual hydroformed header-style runners that keep the exhaust pulses segregated until they dump into the close-coupled catalyst for improved performance.