The Small-Block's Timeline
'55: The small-block V-8 is introduced in '55 Chevrolets as a 265. This is the beginning of the Gen I.
'57: 1/8-inch bore increase raises displacement to 283ci; the Ramjet mechanical fuel-injection system was introduced, bringing horsepower to 283--1 hp/ci.
'62: Displacement increases to 327ci with a 4-inch bore and a 3.25-inch stroke. Ramjet fuel-injected versions are rated at 360hp.
'64: Cylinder head improvements (2.02-inch intake valves) bump the 327's highest horsepower rating to 375 with fuel injection.'67: A little-known option called Z28 is released for the Camaro only, which includes a high-revving 302ci small-block for competition in SCCA Trans Am road racing. A 350ci (5.7L) version (in the Camaro) debuts and will become the quintessential small-block variant.
'68: A Camaro Z28 wins the Trans Am championship.
'70: 350ci LT1 debuts in the Z28 Camaro and Corvette and is rated at 360/370hp respectively; 400ci small-block is offered--the largest-displacement small-block built to date.
'75: With fuel economy prevalent in consumers' minds, a more efficient 262ci small-block is introduced. This engine, offered in the small Chevrolet Monza, makes spark plug replacement next to impossible.
'78: V-6 engine based on small-block design introduced; it would become the Vortec V-6 truck engine more than a decade later.
'80: Last year for the 400 small-block, by now offered only in light-duty trucks.
'82: Fuel injection reintroduced with the Cross-Fire Injection system on Corvette and the redesigned (third-gen) Camaro Z28.
'85: Tuned-port fuel injection replaces Cross-Fire Injection, bringing in the modern era of electronically controlled, port-injected engines.
'86: Aluminum cylinder heads debut as standard equipment on Corvette; block changed to accept new single-piece rear main seal.
'87: Hydraulic roller lifters introduced on fuel injected engines.
'89: The H.O. 350 crate engine offers a ready-built performance engine from the factory, changing the way hot-rodders approach engine-building in the next decade.
'92: The LT1 engine in the Corvette introduces Gen II small-block design, which features reverse-flow cooling, revised cylinder head design, and crank-triggered optical distributor. The engine will later be used in Camaros and will become a favorite of police officers in '94-96 Caprices with a top speed of 140 mph.
'96: The Vortec V-8 engines are introduced in trucks, featuring cylinder heads with swirl-inducing combustion chamber design to increase power and torque.
'97: Gen III 5.7L LS1 small-block introduced with all-new Corvette, featuring all-new deep-skirt block casting with six-bolt mains, redesigned cylinder heads with symmetrical ports and combustion chambers, and coil-near-plug ignition system.
'99: Gen III-based Vortec V-8 engines introduced in GM trucks; displacements include 4.8L, 5.3L, and 6.0L.
'00: The Z06 debuts with the LS6 engine pumping out 385 hp.
'05: The Gen IV small-block is introduced 50 years after the original. LS2 and LS7 are part of this engine series.
'06: 7.0L LS7--introduced in Corvette ZO6--becomes the largest, most powerful small-block ever built.
--GM Powertrain