273 "LA" Engine

1964-69 • 3.63" bore x 3.31" stroke
Realizing the need for a lighter V8 engine for use in the smaller vehicles then coming on the scene, Chrysler designed its first "thinwall" small block. Known as the "LA" engine series, the first engine out of the box was the 273. Light and compact, the 273 posed much less of an engineering challenge to fit in the new A-body chassis. While never intended to be a powerhouse, high compression, solid-cammed 4-bbl versions of the 273 did run well in cars like the Barracuda Formula S.

318 "A" Engine

318 "LA" Engine

1967-and-later • 3.91" bore x 3.31" stroke
Even though physically the 1967 318 "LA" V8 shared little more than bore and stroke dimensions with its "A" engine cousin, the two were identical with respect to their intended use. The "new" 318 was the base V8 powerplant for the entire Chrysler product line. Because of its lowly status, the 318 didn't even receive a 4-bbl carburetor and manifold until 1978, when the 360's setup was borrowed for use on the little workhorse. While the 318's pedigree may not match that of the Hemi, the fact that with a few modifications it's still in production some 30 years later speaks very highly of the engine's capabilities.

340 "LA" Engine

1968-73 • 4.04" bore x 3.31" stroke
The 340 should be considered the "Hemi of the small block family". Why? Simply because the 340 was designed from the outset as a performance engine. Look at the stats: high compression, big valves (2.02 intake, 1.60 exhaust), forged and shot-peened crank and rods, etc. These engines were built to perform well and stay together doing it. A testament to the 340's power potential is the fact that Chrysler installed the beefy A-727 Torqueflite automatic behind it instead of the usual 904, the only small block to receive such an honor. 340 development peaked with the 1970 6-bbl version available only in the limited-edition AAR 'Cuda and T/A Challenger (which were Dodge and Plymouth's entries into the SCCA's Trans-Am road racing series). Considerably underrated at 290 horsepower at 5000 rpm (not coincidentally, Chevy's Z/28 302 and Ford's Boss 302 were also rated at 290 horsepower), by turning it higher, which it was more than willing to do, resulted in much more power. The 6-bbl 340s had beefier blocks with thicker main webs to go along with the forged crank and rods. The cylinder heads were also unique to the 6-bbl engine. Chrysler relocated the intake pushrods, which allowed a much larger intake port opening and thus more flow. The valvetrain was adjustable, and induction chores were handled by three Holley 2-bbls on an aluminum intake manifold. In late 1972, with factory performance nearing an end, the 340 got a cast crankshaft and heads from the 360. But as far as small blocks go, the 340 is legendary.

360 "LA" Engine

1971-present • 4.00" bore x 3.58" stroke
Being the biggest of the small blocks doesn't necessarily mean that it was the best performer. Though only equipped with a 2-bbl and a relatively low compression, the 360 was still able to turn out 255 horsepower (gross rating) in its first year of production. The following two years weren't so kind to the 360 with horsepower levels falling to 175 and 170 respectively. Help did arrive in the form of a 4-bbl carb in 1974 though, and power rose to 245 net horsepower. Interestingly enough, the 360 is still in production, and the latest versions still generate 245 net horsepower. The beauty of the new engine is that through fuel injection and computer controls, this level of power is possible with good fuel mileage and low emissions.