The Vortec 7400 is just an old-school 454 with high-tech parts.
Also known as the Vortec 7400 (7.4L, Regular Production Option designation L29), Chevrolet’s Vortec 454 was a modern-day evolution of the company’s most legendary big block. The 7400 was essentially the same big block 454 that carried Chevy through the muscle car years, but a hydraulic roller camshaft and revised cylinder heads helped to make it far more efficient than the old LS6 could ever dream of being. Even so, this engine was built primarily to provide huge towing power for CAFE-standard exempt vehicles, so there remains some room for improvement.
1. Switch to a lightweight synthetic oil. Although Chevrolet doesn’t specifically recommend it for this engine, the extreme slipperiness of a full synthetic will allow you to run a thinner weight oil without worrying about undue engine wear. Thinner oil drags less on internal engine parts, helping the engine to spin more freely and run more efficiently. After all, every horsepower lost to such “parasitic drag” is one less that won’t be helping your truck move down the road.
2. Install a high flow air filter and cold air induction intake. A restrictive or clogged air filter will force the engine to work harder to breathe, which makes it less efficient. A cold air induction setup will feed the engine cooler and more oxygen-dense air. These modifications will help to generate more horsepower without adversely affecting fuel efficiency, which will ultimately increase net mileage.
3. Use a set of long-tube headers (exhaust manifolds) and an aftermarket exhaust system. That extra air going into your engine needs to get out somehow; installing a full aftermarket exhaust system like this is always good for more fuel economy, especially when combined with a freer-flowing intake. This modification won’t be cheap or easy to install, but will eventually pay for itself if you do a lot of towing or drive a lot of miles.
4. Install an aftermarket windage tray in your engine. Windage trays are thin, sheet metal plates that bolt to the bottom of the main caps and act as a barrier between the oil in the pan and the crankshaft counterweights. Oil tends to collect on the crankshaft counterweights, adding weight to the rotating assembly (crankshaft, rods and pistons) and reducing horsepower through parasitic drag. Inexpensive and fairly easy to install, a windage tray will help to keep oil in the sump where it’s supposed to be and can even help to extend bearing life by keeping the rotating assembly in balance.