What's in the blue box? A...
What's in the blue box? A 360 crate engine rated at 380 hp, ready to run. Will it turn the number? We'll find out.
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.
Brule Talks When we're in...
Brule Talks
When we're in for a dyno test, we always look forward to hearing dyno operator and fellow tuner Steve Brule elucidate our latest subject. We can't think of anyone who's run, tested, and tuned more hardware and combos than "Brullio." In his words,"That's a nice crate motor Mopar's putting out . torque's just where it should be for an engine of this type and size. It pulls strong with a very smooth power curve through the rpm range . no hiccups in the torque band right to and past peak power. This shows the valvetrain combo is well matched-not always the case with a hydraulic roller engine . and did you notice, not a wisp of blow-by?"With all the other brands that go through this shop, we're always proud when a Mopar proves its worth. Now if we could only find him that '67 GTX like the one he had back in the day
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.
Complete from oil pan to intake,...
Complete from oil pan to intake, the crate just needs accessories, pulleys, carb, headers, plugs and wires, and it's ready to fire. The 360 Magnum has a specific balance factor, different from the earlier 360s. The damper comes with it, but the flywheel, flexplate, or converter does not. When ordering, be sure to specify Magnum balance.
What distinguishes the Magnum...
What distinguishes the Magnum from the older LA engines are the heads, the greatest difference being the departure from the open-chamber design to a modern quench-style closed chamber.
Another significant change...
Another significant change is the move to pedestal mount rockers in place of the shaft-mount system found in earlier designs. The Magnums use a higher 1.6:1 rather than the traditional 1.5:1, delivering more lift to the valve for a given cam profile.
We mounted the crate to Westech's...
We mounted the crate to Westech's dyno to see what it is capable of doing. Before the distributor went in, we primed the engine using a Mopar Performance priming shaft, PN P4286800.
For pulleys, we ran this unknown...
For pulleys, we ran this unknown brand of underdrive setup that we swiped from one of Car Craft editor Matt King's engines, which he foolishly left unguarded.
The 380-horse crate is fitted...
The 380-horse crate is fitted with a Mopar Performance M-1 single-plane intake-a nice piece that proved exceptionally well-matched to the combo. Note the unique Magnum bolt angle, which is different from the earlier LA engines.