Hot Rod Magazine, August 1955, 1st page

Packard's bold bid for power includes a radical new chassis and the industry's biggest engine

The veil of secrecy that shrouded the new Packard V8 has been surpassed only by the Iron Curtain. Usually, new automotive developments are released to members of engineering groups and the press some time before the cars fill the showrooms, but this year Packard withheld specific information of two very significant innovations. Meanwhile, a few expert rumormongers had a field day. According to them, the new Packard V8 engine was a 400-cubic inch, two- cammed affair with an aluminum block. The actual result is slightly less spectacular, but nonetheless quite worthy of a detailed discussion.

In 1946, Packard instituted an engine development program to explore the possibilities of new and novel designs suitable for future production as successors to the venerable straight eight. To be sure, many unusual designs were tested and evaluated, as were new methods and materials (including aluminum cylinder blocks). By 1949, most of the details of the new Packard engine were established; that is, nearly everything except the piston displacement which was originally set at 269' cubic inches. The leaps and bounds by which other manufacturers increased piston displacement, power and torque prompted Packard engineers to reconsider and redesign, so they wouldn't be caught flat-footed with an engine that would be underpowered to sell the increasing numbers of performance-conscious buyers. So they went to the other extreme and made the production engines big, with provisions for going bigger whenever the need arises.

Currently, the Packard Division of the newly formed Studebaker-Packard Corporation is supplying 320-cubic inch V8 engines for both the '55 Hudson "Hornets" and the Nash "Ambassadors." Basically, these, are "detuned" versions of the 320-cubic inch Clipper engine,

which, in turn, is a smaller edition of the engine used in the Clipper "Custom," Packard and the Packard "Caribbean" models.

Packard engineers have never shied away from building engines of mammoth proportions and their latest effort is automatically a unanimous choice for the world-famous (but mythical) organization, "There Ain't No Substitute for Cubic Inches" Club, of which I modestly proclaim I am mythically president. This 352-cubic inch monster has a four-inch bore and a 3 1/2-inch stroke, which results in the favorable stroke/bore ratio of .88 to 1. The maximum advertised brake horsepower is 260 obtained at an engine speed of 4600 rpm and maximum advertised torque is 355 pounds-feet between 2400 and 2800 rpm. The same size engine in the Clipper "Custom" produces 245 brake horsepower at 4600 rpm and 355 pounds-feet of torque at 2600 rpm. The smaller 320-cubic inch engine (3 13/16-inch bore, 3 1/2-inch stroke) in the Clipper "DeLuxe" and "Super" series yields 245 brake horsepower at 4600 rpm and 325 pounds-feet of torque at 2600 rpm. Both the Hudson and Nash versions put out 208 brake horsepower at 4200 rpm and 300 pounds-feet of torque at 2300 rpm. These values were obtained under the fol1owing conditions: The water, fuel and oil pumps were connected and operating; the generator was rotating but was not charging; the spark advance was manually adjusted for best torque; dynamometer exhaust collectors were used; intake manifold heat was blocked off; fuel was 93 octane Research gasoline; no fan or carburetor air cleaner was used. The dynamometer figures were corrected for a temperature of 68 degrees F. at 29.92 inches of mercury.

It should be realized that advertised power and torque figures do not

represent "as installed" values. With the engine in the car and with the stock exhaust system hooked up, an air cleaner and fan installed, a "hot" intake manifold and a load applied to the generator, plus under- the-hood temperatures of around 100 degrees F., the power and torque will drop off on an average of about 14 and 12 per cent, respectively. Even so, the big Packard has the edge on all competitors in all departments; the displacement is 3.2 per cent larger than its closest rival, the advertised power is four per cent higher and the advertised maximum torque is 2.9 per cent more. This engine also scores in the matter of engine weight, the whole issue with all accessories except the air cleaner, tipping the scales at 698 pounds.

The 210-pound cylinder block is cast with the usual 90- degree span between cylinder banks from close-grained alloyed iron. The blocks for both engine sizes are identical except for the cylinder bore diameters and the coring of the cylinders. The upper half of the bell housing is an integral part of the block. Five transverse bulkheads separate the cylinders of each bank and are used as supports for both the crankshaft and the camshaft. The main bearing caps are located 1/4 of an inch above the oil pan surface in longitudinally broached recesses. The cylinders are surrounded by full-length water jackets, except at the inboard sides, where the jacket length is reduced to make room for the valve lifter bosses and two longitudinal oil galleries.

Distortion of the cylinder bores is minimized by tying the cylinder head screw bosses into vertical ribs. The center- to-center distance between adjacent cylinder bores is five inches, which leaves a minimum of one inch between bores (1 3/16 inches in the 320-cubic inch engine) for a head

Next page