Corvette Engine Selection - Project C4orce Update

If you've been paying attention, you've probably noticed that coverage of Project C4orce has been blatantly absent for quite a few months. Ye of little faith have undoubtedly concluded that the project has been abandoned, sold by aliens, or worse. In fact, it has suffered the fate of so many long-term projects-unforeseen problems and scheduling conflicts that inevitably lead into a series of stalls, detours, and U-turns.

Part of the problem is that the project took on a life of its own. The original concept was to produce a high-tech C4 for less than $15,000. We're still on track to do that, but as the project has progressed, feedback from readers and project sponsors made it apparent that Project C4orce needed a special appearance in addition to special performance.

Another aspect of the project's evolution is a need to expand the C4orce concept of documented and registered vehicles to cover C5s and C6s. Consequently, we've been developing components and packages that will apply to '97-and-later Corvettes. The accompanying matrix shows the engine combinations that will be found under the C4orce umbrella and will be available for purchase very soon.

It starts with the 5.3L LS-series engines originally installed in trucks, SUVs, and late-model Impalas. These engines, which are available with cast-iron and aluminum blocks, are relatively easy to find at reasonable prices (especially those with cast-iron blocks). As you may remember, we paid $700 for a complete 5.3L engine (including starter, alternator, A/C compressor, PCM, and harness) for Project C4orce. This wasn't a one-time deal. Johnson Thomas, who works with us on some projects, purchased an almost identical engine for the same price and is installing it in an '88 Third-Gen Camaro.

Since there's no substitute for cubic inches, (or cubic centimeters, if you're metrically predisposed) and to accommodate owners of C5s and C6s, we decided to put together a selection of C4orce engines, based on original bore/stroke configurations. Since all LS-series engines, except the 4.8L truck engine and the LS7, have the same stroke (3.622 inches) that's obviously the dimension to use for all engines that incorporate a stock crankshaft. If you're going to use an aftermarket crank, the logical stroke dimension is 4.00 inches. It's sufficiently longer than the stock stroke to put a bulge in the torque curve and is coincidentally the same length as the crank in LS7 engines.

Overall displacement specifications will vary to some degree depending on finished cylinder bore diameter, but the C4orce standard engine package specifications are based on commonly used reference dimensions. Engines and rotating assemblies with other bore/stroke dimensions will be available on a special-order basis.

One of the advantages of standardizing bore/stroke combinations is enhanced availability and parts interchangeability. As an example, if you find a great deal on a 5.3 engine and decide to build it with a 4.00-inch stroke, you'll wind up with 6 liters. If you subsequently decide that bigger really is better and acquire a block with a 3.900-, 4.000-, or 4.060-inch bore, you can pull the rotating assembly out of the 5.3, order the appropriate pistons, and reuse the existing crankshaft and connecting rods. Since the C4orce connecting rods and 4-inch crankshaft rods are the same, regardless of the block in which they're to be installed, these components should never be out of stock.