Mopar Small-Blocks. Larry Shepard

in the engine’s design was having less weight; after all, it was going to be installed into smaller, lighter vehicles.

      A Bit of History

      The new engine went into production in 1964 as the 273 LA-engine. Its name, “LA,” comes from one of its three major design parameters, lightweight A. The new engine was designed and developed under the engineering code of A828.

      1965

      In 1965, the 273 engine was upgraded to 235 hp with the addition of a 4-barrel carb, high-performance cam, higher compression ratio (10.5:1), and black-painted valvecovers. This high-performance package was developed under the A861 engineering code. Next was the 318 with a bigger bore (3.91). The new 318 also had hydraulic tappets and cam and stamped steel rocker arms, and it was rated at 230 hp.

       The old-style 318 or the original A-engine, also called the poly-sphere engine, shares the same displacement number (318) with the new LA-engine, but the old engine’s valvecover is held on by only two screws: one on each end.

      The new V-8 engine was originally referred to as the A-engine. The A-engine was the older version introduced in 1956. Over the 30 years of production, this distinction has been lost and all 1964 and newer small-blocks are now referred to as A-engines.

      1968

      In 1968, the performance version of the A-engine was introduced as the 340. The 340 engineering code is A105 and it features a big bore (4.04 inches), bigger valves (2.02/1.60 inches), high-flow, bigger-port cylinder heads, heavy-duty forged steel rods, beefed-up block and mains, bigger hydraulic cam, high-rise intake manifold with larger runners, high-flow exhaust manifolds, viscous fan, and windage tray. The result of all this hardware was a 275-hp rating with 340 ft-lbs of torque.

      1970

      The 340 6-barrel engine (called the A340) was added in 1970 in the Trans-Am cars (called Challenger T/A and AAR Cuda), which were intended for SCCA Trans-Am road racing. The 340 6-barrel engine package featured three 2-barrel Holley carbs, an aluminum high-rise intake manifold, modified cylinder heads, adjustable valve gear, and heavy-duty 340 block bulkheads for potential four-bolt mains. The engine was rated at 290 hp and 345 ft-lbs of torque. The 340 6-barrel was only produced in 1970.

      1971

      The final production A-engine displacement increase was introduced in 1971 as the 360 engine. The 1971 360 was built only as a 2-barrel carburetor, which continued for the first three years of production. It was introduced just prior to the new federal emissions laws of 1972, which required the use of low-octane fuel, which required lower compression ratios. The engine was originally built in Chrysler’s Windsor, Canada, engine plant.

       The 1964–1967 273 LA-engine looked small, but it is actually the same size as the 340 and 360. The bigger engines got bigger air cleaners and high-rise intake manifolds that make them look bigger.

       The 340 was Chrysler’s standard high-performance engine for many years. The basic parts of the 340 package were very good performance parts.

       One of the higher-output crate engines, and certainly one of the largest small-blocks, was the 408-ci version with aluminum heads.

       A unique crate engine was the Magnum MPI version (360 or 5.9L) with the high-flow intake manifold.

      The new 360 engine featured a longer stroke (3.58 inches) at the stock deck height (no raised block), 4.00-inch bore, smaller intake valve (1.88 inches), external-balance weights at each end of the crankshaft, and cast crank with larger main bearing diameters (2.81 inches). It also included block core holes similar to the 340 lined up on the halfway point between the adjacent bores, which allows steel shot to have better aim and access to the water-jacket in the cleaning process to clean out core-sand. In addition, the main bolt spacing was increased by .31 inch. With an 8.7:1 compression ratio, the result was a 255-hp rating.

      1974

      From a performance standpoint, 1974 was a milestone date because the 360 replaced the 340 as the small-block performance engine. It was generally called the E58 engine option and used the 1972–1973 340 Thermo-Quad carb, 360 heads with the 1.88-inch intake valves, bigger 340 hydraulic cam, and 340 high-performance valvesprings, which resulted in a 245-hp rating with 320 ft-lbs of torque. This change took place during the first 1974–1975 gas crisis, which introduced fuel economy concerns.

      1978–1985

      The first 318 4-barrel engine was introduced in 1978; it used the Thermo-Quad carb. In 1981, the 318 was introduced with fuel injection in the Imperial only. This option continued through 1983. In 1985, the 318 engines were introduced with hydraulic roller tappets and roller cam with higher compression and a 140-hp (up from 130) rating.

      1992–1993

      The new Magnum 5.2L V-8 engine package replaced the 318 LA-engine (commonly called the A-engine) in 1992.

      The new Magnum 5.9L V-8 replaced the 360 in 1993. These engines were originally placed in Dodge pickup trucks then Jeeps; rear-wheel-drive cars were added at a later date. Magnum engines had high-tech electronic fuel injection or multi-point fuel injection, hydraulic roller cams, revised valve gear for an oil-through-the-pushrod oiling system, and revised heads and valve sizes (1.92/1.625 inches).

      Today

      From the introduction of the LA-engine in 1964 through the end of production in the early 2000s, small-block engines were installed in many special cars, such as the 1970 Trans-Am E-Bodies, the 1978–1979 Little Red Express truck, the 1970 340 Duster/Demon, the 1974–1976 360 Dusters, the 1978 Street Kit car and Super Coupe, the 1993 and newer Dakota R/T 360, and the 1966 D-Dart.

      Racing Highlights

      For this book, I wanted to organize the various racing highlights into something that made sense, but I couldn’t come up with a title for each category until I settled on “Phase.” My five categories (covering 40 years!) start and stop, but there is much overlap.

      Phase One

      The first phase began in 1964 with the introduction of the 273 V-8 and ran through the end of 1969. During this period of time, Chrysler was heavily involved in racing big-blocks, both Hemis and wedges. The first competition for the small-block V-8 was the 1964 Mobil Gas Economy Run.

      The small-block cars had many first-place finishes in A- and B-Body cars. Small-block engines continued to compete successfully in this series that ran through 1968. The engine also competed successfully in the Union Pure Race Trials. In 1966, in the inaugural SCCA Trans-Am road racing series, Bob Tullius (in a 1966 Dodge Dart) and Scott Harvey (driving Team Starfish’s 1966 Plymouth Barracuda Formula S) both competed with the 273 V-8. With the introduction of the 340 in 1968, the A-engine competed in NHRA/AHRA drag racing classes, mainly within Stock eliminator.

      In 1969, Chrysler launched the P69 program, an Indy racing program that allowed a stock-block engine to compete with the racing-specific engine. The P69 program used the LA-engine block at 318 to 330 ci. Two cylinder heads were used: a modified wedge head for short tracks and a raised-port special head for speedways.

      Phase Two

      This could be considered the first push in small-block performance, and it begins roughly in 1970 and ends in 1971–1972. With the introduction of the 340 Duster in 1970, racing in the NHRA/AHRA Stock and Super Stock classes became more popular, led by Ed Hamburger.

      In