Fix It

Chevrolets 454 Big Block engine has been through several phases over its production span. The engine began as a major player in the muscle car wars of the 1970s, gaining notoriety for its ability to generate serious horsepower and torque. Displacing 7.4 liters, this V8 was never intended to be fuel efficient, but rather was paired with a four barrel carburetor for maximum output.

Background

In the height of the muscle car era, as car manufacturers focused on designing engines that were larger and faster, Chevrolet introduced the 454. This throaty powerplant was reserved for high performance upgrades on Camaros, Chevelles and Corvettes. The 454 especially enhanced the reputation of the Chevelle as a muscle car.

Shortly after its introduction, climbing gas prices and increased regulation on auto emissions influenced auto makers to focus on smaller engines. The 454 was transferred to Chevys truck line and used in its heavy-duty half and three-quarter ton pickups. In the mid-1990s the engine was redesigned and renamed the Vortec 7400, before being phased phased out of production in 2000.

Performance Specifications

The 454 was available as an LS5, LS6 and LS7 in the 1970s. The most powerful version available to the public was the 1970 LS6. When installed in the Chevelle or Camaro, this engine could deliver 450 horsepower at 5,600 rpm. In the Chevelle, the LS6 had a maximum torque of 500 ft-lbs at 3,200 rpm. Camaros could also achieve this torque at 3,600 rpm. The horsepower was decreased when the 454 was transferred to pickup trucks. When the 454 was first introduced as the Vortec 7400 in 1996, it was rated at 290 horsepower.

Engine Specifications

This 7.4 liter engine is one of the larger engines made by Chevrolet. The 1970 to 1974 high performance versions had a 4.00-inch stroke and 4.251-inch bore. The timing order is 18436572, with a distributor cap that spins clockwise. Engine oil is the primary lube or sealer, and is used on the main caps, connecting rod bolts, cylinder heads, oil pump and pan, timing cover, valve cover, centerbolt and on the bellhousing between the transmission and the engine block.

The Chevy 454 is a popular and reliable hot-rodding engine that has been around since the 70s. Cubic inches translate into horsepower every day of the week, and the 454-cubic-inch Chevy engine creates a lot of horsepower. The Chevy 454 engine is traditionally known as the Rat motor (as are the 396 and the 427 engines), whereas Chevys smaller engines are referred to as the small block. The 454 lifters will last a long time with proper oil changes.You can remove a lifter from a Chevy 454 engine without any specialty tools.

Instructions

1

Lift the hood and prop it open. Slide a drain pan under the radiator and open the drain cock. Drain the coolant from the radiator. Remove the top radiator hose from the radiator and the intake manifold.

2

Snap a photo of the top of the engine with your cell phone camera. This will to aid reassembly.

3

Remove the air cleaner. Disconnect the fuel line and the throttle cable, or the linkage if so equipped, from the carburetor.

4

Remove the distributor cap from the distributor. Make a mark on the distributor housing corresponding with the electrode on the end of the rotor button. This makes it easy to realign the rotor button with the distributor when reinstalling the distributor. Unplug the distributor, loosen the distributor hold down clamp and slide it back, and lift the distributor shaft out of the intake manifold.

5

Loosen and remove the bolts that attach the valve covers to the cylinder head. Remove the 12 bolts that attach the intake manifold to the cylinder heads. Tap a straight screwdriver blade between the intake manifold and the block. The intake manifold is sometimes glued down with gasket cement.

6

Loosen the rocker arms on all the valves that need the lifters replaced. Record the number of full and partial turns the rocker nuts are turned on each rocker to ease reinstallation.

7

Remove the push rods from the top of lifters that are to be removed. Record where each push rod was located so that you can reinstall them in the same place in the same position.

8

Grip the top edge of the lifter to be removed with a vise-grip pliers and rotate it while pulling up on it. Sometimes the bottom of the lifter gets a build-up of varnish on it, and it takes a bit of rotating and pulling to remove the lifter from its bore.

9

Reinstall the new lifters. Reposition the push rods in the exact same hole they were in, in the same position. Replace the rocker arm on top of the push rod and valve stem. Thread the rocker arm nuts back onto the studs the same amount of turns needed to remove them.