This LS1 engine, installed...
This LS1 engine, installed in an '01 C5 has been given the C4orce treatment, which includes ported LS6 cylinder heads, a ported throttle body, a C4orce camshaft, and C4orce special tuning. It produces 449 hp at the wheels, idles at 800 rpm, and can be driven at 1,000 rpm in Sixth gear with the original 3.42:1 rear gears still in place.
C4orce engine packages tremendously expand choices for C4 owners and also provide a number of options for C5 and C6 owners by offering combinations for virtually all popular LS-series production blocks. That makes it easy to put an engine together with parts already in hand, rather than making it a necessity to use only newly purchased components. One of the few major components that may lead to a state of confusion is the crankshaft. Although the forgings are physically identical, if an engine is to be controlled by an LS1-style PCM, a crankshaft with a 24-tooth reluctor must be used. If an E38 or E40 ECM is going to be calling the shots, a 58-tooth reluctor is necessary.
As is the case with all C4orce components, all engines are designed to deliver great value. One example is the 417ci LS3 combination. While its horsepower potential is somewhat lower than that of an LS7, its costs are significantly lower. An LS3 block and a pair of assembled cylinder heads cost approximately the same amount as a bare LS7 block. With a reasonably mild camshaft, initial testing indicates our 417ci LS3-based engine should put out 525-550 hp at the wheels.
We've also developed a stock-displacement LS1/LS6 combination that puts out 450 hp at the wheels, and a really mild 5.3L package that produces 330 hp at the wheels (for reference, a stock 5.3 engine typically cranks out 250-260 hp). A more aggressive 5.3L package, like the one that's installed in Project C4orce, produces about 375 rwhp.
With all of these engine combinations, our focus has been on combining efficiency and reliability with a broad powerband. While this might not deliver the numbers necessary to win "can you top this" contests, it will deliver engines that produce power curves that optimize driving fun, and the ability to demonstrate that when it comes to horsepower, sometimes less is more-as in less at the top end and more in the middle equals better overall performance.
The C4orce engine matrix is a work in progress, so it will be changing and expanding over the next few months. In addition to partial and complete engines, we'll also be adding a variety of individual components and assemblies to the C4orce program. Look for periodic updates in future issues of Corvette Fever.
 One of the reasons we selected...  One of the reasons we selected a 5.3L iron block truck engine for installation in Project C4orce is that it's readily available at relatively low cost. These engines have been used in GM-produced trucks and SUVs since 1999. In stock form, they're rated at 285-315 SAE net horsepower (depending on model year), which provides an excellent base for additional power options. |  One of the outgrowths of the...  One of the outgrowths of the C4orce program is this motor mount adapter plate that greatly simplifies installation of LS-series engines C4 Corvettes and a variety of other vehicles. After the plate is bolted to the block, a conventional small-block-style motor mount can be bolted to it, and the engine is ready to be mounted in the chassis. |  Another out-growth of the...  Another out-growth of the C4orce program is a set of headers designed specifically for LS-series engines installed in C4 chassis. Manufactured by Melrose Headers in Cortland, Illinois, they feature 1 3/4-inch-diameter primary tubes and 3-inch collectors. |
Click here for the bore/stroke combination chart