Drivetrain Drop
A new engine was a given, but what would it be, another 318? The answer came when the second stroke of luck came my way, a remanufactured 360 engine found at the wrecker's in an '83 one-ton chassis cab truck ('79 block). The low compression 360 would allow the engine to run on cheap 87 octane regular gas while the added 40-plus cubes of Mopar's biggest small-block would provide the torque to propel this heavy luxo-barge down the road like a musclecar. Tweaked on the dyno with a Comp XE 262 cam kit and an Edelbrock EGR manifold, the low-compression 360 turned in 335 hp and a fat 400 ft-lbs of torque in a package that should pass the smog test (see "Smog Dog Dyno Flog" - May 2001). Engine: done.

Next, what about the rest of the drivetrain? The stock 904 was an unknown quantity, and the small Torqueflite was never used in a factory application behind a 360. Also, all 360s are externally balanced, and thus no production small Torqueflite torque converters were produced with the eccentric balance weight for the 360. This in itself isn't an obstacle, since the appropriate weight can be welded onto a 904-style torque converter (we've done it in the past), but for street reliability, the larger 727 Torqueflite seemed like a better choice. I already had a built, late-model A-engine 727 in the shop, complete with a special high-stall 11-inch lock-up torque converter-perfect. For this swap, the speedo cable and cooler lines also worked, but the late-model neutral safety switch from the small trans was needed to mate with the late-type wiring connector (the switches interchange). Transmission: done.

With the engine and trans on hand, it was time to turn some wrenches on the Fifth. The 360 is a bolt-in replacement for a 318, though there is a slight variation in the lefthand (driver's) motor-mount lug on the side of the block. The lugs consist of two bolt holes at the front boss and a single hole at the rear boss. The rear boss on the 360 is about 31/48-inch further forward than on the 318. There are narrower engine mounting brackets for the 360, but to use the 318 bracket, all that's needed is a spacer between the rear lug and the bracket. With a 11/42-inch nut for a spacer, the 318's bracket bolted right up. Since the Fifth was originally a two-barrel, a four-barrel throttle-linkage bracket and trans kickdown arm were required, a common item on 318 or 360 four-barrels and found at the boneyard.

The engine and trans were bolted together and dropped into the Fifth as a unit. The trans aligned with the stock crossmember, and used the same mount as the smaller 904. The factory shift linkage also lined up and worked with the 727, though the pivot bracket for the shift bellcrank at the trans needed to be the shorter 727 piece. The kickdown linkage was the original three-piece setup from the smaller trans, which worked, though from the engine pivot-bracket forward, the four-barrel bracketry is required. Even the original trans cooler lines worked perfectly, with a minor amount of tweaking.

Finishing off the engine swap, all of the front accessories and brackets from the 318 were bolted onto the 360, including the original axial air-conditioning compressor. To make sure cooling wouldn't become a problem, an old style Mopar three-row-core H/D 26-inch radiator was grafted to a set of M-Body mounting brackets and mated to a factory shroud. The air is pulled by a huge seven-blade viscous-drive fan, and a Milodon 160-degree balanced-flow thermostat completed this cooling system. As a result, the temperature gauge needle barely moves. To handle the ignition, the factory ESA computer system was shelved in favor of a Mopar Performance electronic ignition conversion kit. The electronic outift certainly isn't a true emissions-legal replacement, but once installed, it looks stock enough to probably get by a smog check.