Chrysler's 380hp crate small-block has become a popular choice for those looking to pop the lid on that big blue box and pull out a stout small-block ready to turn a number. With a rated output of 380 horsepower, and a remarkably flat, and fat, torque curve, the 380/360 has gained recognition as a strong performer. We've seen numerous crate-equipped A-Bodies deep in the 12s with box-stock crates, and in anyone's book, that's fast enough to make the grade as a musclecar engine. The Mopar small-block crates have justly earned a reputation as quality engines at a bargain price, and with reportedly the lowest warranty return rates in the industry, Mopar Performance has this combo down pat.

Based on the production Magnum 360, the 380-horse crate is built with all-new parts, not the usual rebuild. Inside the bottom end you'll find pump-gas-friendly 9:1 pistons, a hydraulic roller cam, and a double-roller drive. The roller is a fairly stout stick, with a long .288 intake, .292 exhaust duration, and .501/.513 lift-much more than any production small-block. The specs don't hide the fact that this cam will have some bark, so if the lope, rumble, and top-end power aren't the goal, consider backing off to the milder 360/300hp version.

Topping the short-block is a set of Mopar's now-familiar high-swirl closed-chamber Magnum cylinder heads. The 1.925-inch intake valves are slightly smaller than those of the early 340, while the 1.625-inch exhaust valves are slightly larger. As with all Magnum engines, 1.6:1 rockers are standard. This is a tenth of a ratio point higher than the traditional 1.5:1 small-block rockers of old.

The major benefit of the Magnum heads over the old 340/360 castings is the nicer form in the exhaust port. The old small-block Mopar heads had a definite flow-inhibiting area in the most critical portion of the exhaust port floor, right as the port departed from the valve seat. Also restricting the exhaust flow was a big kink in the port roof. The Magnum exhaust port is much improved. On the intake side, the port window is narrow through the pushrod area, owing to the larger clearance hole used in conjunction with the hydraulic roller cam's valvetrain. Toward the valve, the Magnum head's ports take a nice form. The most significant departure from the Mopar small-block heads of old is the combustion-chamber design. The best features of the old heads were retained, including the valve angle and favorable opening axis to the centerline of the bore. The chamber has been redesigned to take advantage of the better combustion characteristic available from a modern closed-quench chamber. This chamber design alone should produce a worthy increase in output over the old-style open chamber heads.

The Magnum crates are shipped with a large cross-section single-plane M-1 aluminum intake manifold, which appears to be a nice design, utilizing a modern sweeping runner. Bosses are cast into the intake, allowing for a multi-port fuel-injection system, although a standard four-barrel carburetor is the induction of choice for most installations. The Magnum crate is fitted with a center-sump oil pan, which is compatible with traditional Mopar body styles. Rounding out the package, the crate comes equipped with MP cast-aluminum valve covers, a damper, the dipstick and tube, as well as the water pump. A complete Mopar Performance electronic ignition system and thermostat housing are included. Add a carb, headers, and accessories, and it's ready to run.