Mopar Small-Blocks. Larry Shepard

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СКАЧАТЬ Gary Stanton’s USAC Sprint Car won the Silver Crown championships in 1994 and 1996, driven by Jimmy Sills. Bob Keselowski in a Chrysler LeBaron with a small-block finished second in 1992 and third in 1993 in the ARCA championships.

      Dodge and Mopar Performance returned to the Trans-Am series in 1992 with the Archer Brothers with Joey Arrington engines. Mopar Performance entered the World of Outlaws winged sprint car series in early 1997, which led to Mark Kinser and the all-aluminum Mopar small-block winning the World of Outlaws championship in 1999. Engine builder Gary Stanton and Chrysler’s Lee Carducci led this sprint car engine program.

      Phase Five

      Chrysler returned to NASCAR racing and entered the Craftsman Truck series in 1996. Chrysler and Mopar Performance raced in this truck series consistently using Arrington small-block engines and won the championship with Bobby Hamilton in 2004 and with Ted Musgrave in 2005. The development programs to support this racing series were led by Chrysler’s John Wehrly and Ted Flack.

      In about 1998, the NHRA launched the new Pro Stock Truck class that was limited to small-blocks. Mopar’s small-block was heavily involved.

      The big news came in 2001, when Dodge and Chrysler returned to NASCAR Sprint Cup racing with several teams, led by Ray Evernham and his number-one driver, Bill Elliott. Team Penske ended up winning the 2012 NASCAR championship, with driver Brad Keselowski.

      To race, you have to have parts. In about 2005, Mopar Performance had about 23 small-block blocks and around 30 small-block cylinder heads to service the needs of all the Mopar A-engine small-block racers and the various racing categories in which they competed. Mopar Performance/Chrysler designed and manufactured all of these hard parts; this did not include parts made by Edelbrock, Indy Heads, or B1/Brodix.

      Mopar Performance had always made hard parts for off-road use. However, beginning in 1996, Mopar Performance began developing high-performance parts for the Magnum small-block engines used in Ram and Dakota trucks that were emissions–exempt as certified by the California Air Resources Board (CARB). Therefore, it was legal to sell and install them on street vehicles.

      The Mopar small-block had been so successful in various sprint car racing venues that Mopar Performance developed a 4-cylinder race engine (half of the Mopar small-block) for use in midgets. Jim Szilagyi coordinated this Mopar midget engine program. It was very successful in the early 2000s with several series championships using one A-engine head. It continues today through Gary Stanton Racing Engines.

       CHAPTER 1

       BLOCKS

      The engine’s cylinder block is the basic foundation for virtually everything in an engine project, and as such, it affects almost every part in the engine, either directly or indirectly. Improved performance is the typical goal of an engine project, and to accomplish this basic goal, all parts used in the engine must work together.

      All parts need to be compatible, but they should also be complementary. You may take the engine apart and put it back together several times before you arrive at the final assembly steps to complete the engine. As you begin building your foundation, use a notebook to keep track of everything that you see and do, from casting numbers to bore sizes, etc., for every part that you use. Once the engine is together, it can be very difficult to gain this information and it may be helpful for any troubleshooting that is required.

Block Design

      Basic block design could be considered similar to architecture because it defines how the block is laid out. An engine family such as the LA-engine and the Magnum extension tend to share many features that define them. The LA-engine small-block family is a basic 90-degree V-8. This angle is best for dynamic balance considerations and also makes for a very rigid block.

       Once the block is disassembled or the new block is obtained, it is usually mounted to the engine stand. It is typically mounted upside down or crank-side up because that section is where you are going to start.

       The bare block, no plugs, is the first step in preparation for sending the block to the machine shop. In this common position, the block is upside down and the passenger’s side is toward the left, which can be confusing. If this were a Chrysler race block (cast-iron versions), the large “X” or “R” would be located on the passenger-side face of the block, which is also the passenger-side face as installed in the car. It is on the front of the number-2 cylinder, above the dipstick holes and the core plug.

       Both A-engine and Magnum blocks share the same 10-bolt head bolt pattern, or 4 bolts around each cylinder, but some of the race blocks add 2 more (for a total of 6) per cylinder, and this is covered later in this chapter.

      Cylinder numbering begins with the driver-side front cylinder; number-2 is the passenger-side front cylinder. The A-engine has a production deck height of 9.60 inches; the Magnum group uses 9.585 inches. Small-block race blocks have deck heights as low as 9.0 inches. Both groups of small-blocks share the 4.46-inch cylinder bore centers and the 6.125-inch camshaft centerline height. The LA-engine block is lighter than the original A-engine block and weighs about 160 pounds. The newer 1973–1974 thinwall cast versions are about 4 to 8 pounds lighter, which carries over to the Magnum blocks.

Identification

      Although there are four different cylinder bore sizes, Chrysler made two basic blocks. One is the 273, 318, and 5.2L block; the other is the 340, 360, and 5.9L block. Most A-engines use a motor-mount design that attaches to the sides of the block close to the front, and the mount ears and bolts are parallel to the cam centerline. The 273 and 318 share the same arrangement.

      However, the 340 and 360 share the same driver’s side configuration, but the passenger’s side has the three-bolt pattern reversed.

      The Magnum engine, originally used in trucks, had a three-bolt pattern on each side, and these mounts bolted into the side of the block itself. This bolt pattern is located in the center of the block starting just above the pan rail. In addition, these Magnum blocks had the ears cast in and machined for the earlier system.

      Both groups of blocks have three core plugs per side; the 318 group has them wide-spaced, and the 340–360 group has each core plug aligned with the center of the water jacket between two cylinders.

      The easiest way to identify a small-block Mopar is to compare the casting numbers. Each casting is unique. In other words, you can’t machine out the 273 bores to make a 318. You also can’t make a 340 out of a 318.

      These rules don’t apply to 340 and 360 blocks. You could probably bore out the 360 block to the 340 stock bore size of 4.04 inches, but the 360 has a large main bearing diameter crank. The large main bearing diameter makes the long-stroke 360 СКАЧАТЬ