You’ve heard the rumors. Now hear this…there is a Turbo-Jet 396 from Chevrolet.
You’ve heard its first cousin to the mysterious Mark II Chevrolet engine? It is. You’ve heard how well it breathes and how strong it runs? It does.
We call the beast Turbo-Jet 396, after its displacement. There’s a high output version you can order in Corvette. Bore: 4.094. Stroke: 3.76. Compression ratio: 11:1. One 4-bbl. Mechanical lifters. Bhp: 425. Torque: 415 lb.-ft. That’s what. Now, why.
Breathes deep, free—Combustion chambers in the head are modified wedges with a large quench area for cooling the charge and a close-to-center spark plug for better combustion control. Independent ball-stud rocker arms allow tilting the intake and exhaust valves both lengthwise and crosswise to the engine’s axis.
Tipping the inlet valve toward its port permits less restricted induction along a fairly uniform cross-section. Similarly tipping the exhaust valve allows a gentler outlet radius and less restricted exhaust gas flow. Finally, tilting inlet and exhaust valves away form each other on two axes enshrouds them for maximum volumetric efficiency.
What else id new—the short, rigid block for our Turbo-Jet 396 is strengthened above each bearing support by thick bulkheads. There are four bolts for each bearing cap instead of two. Main and connecting rod journals are especially hardened.
Pistons for this 425-hp version are aluminum impact extrusions developed by Chevrolet for high-output engines. Thermal expansion is controlled by a barrel-contoured skirt, eliminating those long slots below the oil-control ring and strengthening the piston. Connecting rods are beefed up, too.
Mostly, though, it’s the breathing that makes out Turbo-Jet 396 big news. Deep on intake. Free on exhaust. You know how shrouding can strangle an engine.
Not this one.