Swap TricksCompanies like Street & Performance jumped on the Gen III swap wagon early, and the company offers modified oil pans, accessory drives, and other pieces necessary to make your engine swap plans more successful. Painless Wiring and Howell Engine Developments offer wiring harnesses that simplify the swap using the factory computer, while ACCEL/DFI, Big Stuff's, FAST, and Electromotive to name a few now offer the ease of spark and fuel tuning for a serious effort engine swap. Headers and exhaust are the next big areas of development, and we expect to see companies like Hedman and Hooker offering engine swap headers for Gen III engines relatively soon. Hedman already offers a 151/48-inch primary pipe block-hugger header for the Gen III.
Power Potential The Gen III engines are already making a mark in the performance world with plenty of examples of stock 5.7L engines equipped with a mild cam and a good intake like a GMPP LS intake or the new LSX intake from FAST where these engines are making right around 470 to 475 hp. Add a set of CNC-ported heads from one of several companies like Lingenfelter Performance Engineering (LPE) and 500 hp is almost commonplace.
Want to talk stroker packages? Lunati, for one, offers crank and rod packages for the 5.7 to build 383-to-408ci packages that can add serious power and durability with strong 4340 steel cranks and rods. There are also carbureted intake manifolds available now from Edelbrock that allow you to run a carburetor on a Gen III and still use the coil-near-plug ignition with a conversion box. Finally, GM Performance Parts is close to releasing a carbureted intake manifold and a front cover that will mount a distributor to light the plugs. As you can see, in the coming months, the Gen III will be well covered in performance parts.
ConclusionAs the truck Vortec engines, the new GTO, Corvette, and now even the Cadillac CTS-V all come with Gen III and soon to be Gen IV engines, this latest branch in the GM Powertrain tree has already blossomed with several power-producing opportunities. All you have to do is decide which engine will be the focus of your next grand adventure. Take it to the streets, baby.
| By the Numbers |
| Liters | Cubic Inches | Bore/Stroke | Comp. | Rod | Int. | Exh. |
| | | Ratio | Length | Valve | Valve |
| 4.8 | 293 | 3.780/3.268 | 9.5 | 6.276 | 1.890 | 1.551 |
| 5.3 | 325 | 3.780/3.622 | 9.5 | 6.098 | 1.890 | 1.551 |
| 5.7 | 346 | 3.898/3.622 | 9.5 | 6.098 | 2.000 | 1.551 |
| 5.7 | 346 | 3.898/3.622 | 10.1 | 6.098 | 2.000 | 1.551 |
| 6.0 | 364 | 4.000/3.622 | 9.4 | 6.098 | 2.000 | 1.551 |
| 6.0 | 364 | 4.000/3.622 | 10.0 | 6.098 | 2.000 | 1.551 |
Power CurvesThe power numbers listed here are only a fraction of all the different power levels. We've chosen to illustrate the range by showing early numbers followed by the most recent '04 power levels. Note for example that the '04 Corvette LS1 now makes almost 15 percent more horsepower than it did in the '98 Camaro.