We Build It, Small Block Chevy

At the penultimate station, the engine is hooked up for an air-decay test. This putrid-sounding exercise checks the engine for leaks. All the coolant and lubrication holes are plugged, and compressed air is applied to the oil circuit (2-3 psi) and the cooling circuit (20 psi). The system must hold pressure for 2.5 minutes. If pressure drops, the operator squirts the engine down with soapy water, which bubbles wherever the leak is, and sends it offline for repair. The block casting itself is tested at the foundry, so porosity problems never turn up here, but poorly seated gaskets often do. Fixing them here prevents a lot of spots on the driveway. Our trainer engines are known to leak like sieves, so we don't bother hooking it up, advancing instead to the final station.

Here, the flywheel and clutch are attached. A refreshingly low-tech touch: A bent valve placed in a bell-housing attachment hole engages the ring gear on the flywheel to keep the engine from turning while the bolts are torqued. Then a computer spits out the results of all the bolt-tightening operations. Our printout indicates we completed all 293 operations successfully, but it took us 367 attempts to make that happen, whereupon we are encouraged to keep our day jobs.

After completing a 21-point visual inspection, the constructor applies his or her nameplate to the engine. Unfortunately, it goes on a fuel-rail support, which gets covered up by the engine shroud. Signed engines then proceed to another corner of the building, where they're mounted to a special dynamometer and started for the first time. It runs just long enough for the machine to determine where weights need to be inserted in the harmonic balancer and/or flywheel to achieve perfect balance (the original small-block was among the first mass-produced V-8s to benefit from dynamic balancing).

Finished, balanced engines are shipped offsite for a full-load, 20-minute hot test en route to either the Bowling Green Corvette plant or a lucky GM Performance Parts catalog shopper--yes, this fall, hot-rodders and racers alike will be able to buy an LS7 crate motor. Trust us--buying is safer and far more efficient than the do-it-yourself approach.