The engines will now be disassembled and discussed piece-by-piece as far as what is different, what is interchangeable, and what is available for special parts. Later on we will put these pieces together into packages which will be helpful in improving your engine's performance.
A. Cylinder Block
There are two basic slant six blocks. One for the 170 engine and the other for the 198 and 225. An aluminum block was produced in 1962 but is no longer available. The cylinder block is not serviced separately and can only be purchased as a block-with-pistons assembly. The part number for the 170 block assembly is 2463395 while the 198 and 225 share the same number - PN 2951694 (thru 1974). The '75 225 assembly is 3462605. The 1976-77 225 engines are PN 4041314 forged crank and PN 4071072 cast crank. The cast crank has a special block and the pieces are unique. All the blocks are four-main-bearing designs.
Each engine has a different crank. The 170 is PN 2843941, the 198 is PN 2951979 and the 225 is PN 2899582. They all have the same main bearing journal diameter of 2.750" and also the same crank pin diameter (rod journal diameter) of 2.189". They also all have four main bearings. While the 225 crank will fit in a 198 engine (with the correct rods), the 225 crank will not fit in a 170 engine - it interferes with the block. The 1976-77 forged crank for the 225 is 3830099, while the cast crank is 3751036. The cast crank is not interchangeable with the forged crank. The forged crank was phased out of production at the end of 1976. The cast crank engines can be identified by an "E" stamped next to the engine number (i.e. 225E).
The best crank to use for heavy duty six cylinder applications with the 225 engine is the 225 truck crank which is shot-peened. The number for the trucko crank is 2899582 (with pilot bushing).
In 1968 the slant six's crank flange was changed. The flywheel pilot and torque converter nose diameters were enlarged on the newer cranks. These cranks are interchangeable except for this. The '68-69 large pilot crank for the 170 engine is PN 2843941. The 198 and 225 listed above are large pilot cranks.
The flywheel-flex plate attaching bolt pattern for the six is unique. It has six bolt holes, but they are located in a different pattern than the "A" or "B" engines.
C. Cylinder Head
All slant six cylinder heads are interchangeable. There are no major differences between the various heads. The simplest way of identifying the various heads is by the head casting number. From 1964 to 1966 the cylinder head casting PN 2206035 was used. In 1967, a new head (casting PN 2843169) was introduced with a slightly revised combustion chamber shape. This head was still used in 1973 in some applications. In 1971, another new head (casting PN 3614850) was introduced for emissions. In 1975, the latest head was introduced and has casting no. PN 3698444 (1). The casting numbers can only be used to identify the heads. The following chart shows the '64 and newer six cylinder heads and the part numbers that they can be purchased under.
Head Casting Year Number Service Number ---------------------------------------------- '64-66 2206035 2463476* '67-74 2843169 2843819* '72-73 3614850 3671636 with air injection '72-74 3698995 3671476 '75-77** 3698447 3830329 '78 3698447 3698448 '79-80 4104362 4095776 '81-83 4095778 4095776-4104363* Both service heads PN 2463476 and PN 2843819 have been superseded by PN 2847116.
** This new casting no longer uses the spark plug tubes. It also uses the small "BL" series spark plugs and the tappets can't be removed with the head installed on the engine.
D. Valve Cover
All slant six valve covers are interchangeable. The 1974-77 valve cover PN 3769672 has remained unchanged. There is a chrome valve cover P3690742 ('60-'80) available that fits all slant sixes. The '81-'82 cylinder head changed and caused the valve cover on the '81-'82 engine to change shape. They are not interchangeable. The chrome '81-'84 valve cover is PN P4120930.
1. Valve Cover Accessory Package
P4120272 Package comprised of
(12) chrome plated screw and washer assemblies
(1) chrome plated oil filler cap
(2) rubber grommets
2. Chrome Breather Cap
The final touch for your chrome valve cover.
P4120446 Chrome Breather Cap
E. Main Bearings
Crank main bearings come in two materials, F-77 Tri-Metal recommended for oval track cars and long life durability and the softer materials (alum. or babbitt) for drag and other race cars and very high rpm. The recommended main bearings clearance for racing should be 0.002" to 0.003". Includes upper and lower shells. All are 1/2 grooved.
P4286924 '60-'76, Forged Crank, Alum., Std. Size P4286927 '60-'76, Forged Crank, Alum., .010 Undersize P4286930 '60-'76, Forged Crank, Tri-Metal, Std. Size P4286933 '60-'76, Forged Crank, Tri-Metal, .010 Undersize P4286928 '76-'84, Cast Crank, Babbitt, Std. Size P4286934 '76-'84, Cast Crank, Tri-Metal, Std. Size
The main bearings are not interchangeable between the cast and forged crank engines.
F. Vibration Damper
The 170, 198 and 225 all use the same vibration damper PN 2806211. The '76-77 cast crank engine uses a different damper PN 4071060. They should not be swapped.
The best production cam available for the slant six engines was used in the 1971-1977 engines. This cam (PN 3512639) has a 244 degree duration, 26 degree overlap and a lift of .406" on the intake and .414" on the exhaust. The valve lash of this cam should be .010" on the intake and .020" on the exhaust. Both of these settings are hot.
In 1960 Plymouth introduced the Hyper-pak 6 which used a more radical cam (PN 2205620). This cam has a duration of 276-268-44 degrees and a lift of .430".
This camshaft is no longer available from Chrysler but can be purchased from Melling Tool Co., P.O. Box 37, Jackson, MI 49204. Their part no. is RPD-3.
The hydraulic cam and lifters were introduced in 1981. The cam is PN 4105275. It uses a different valve gear than the mechanical cams.
High performance cams are covered in a later section.
H. Sprockets & Chain
All the slant sixes use the same timing chain and sprockets. The timing chain is PN 3514866, crank sprocket is PN 2128912, and the cam sprocket is PN 2806945. These pieces are not for a roller chain design. There is a special set of pieces to convert the slant six to a roller chain system: cam sprocket P4007715, crank sprocket P3690280, and a roller timing chain P3690279.
J. Connecting Rods
Each displacement slant six engine has its own connecting rods. The 170 rod (PN 1947165) has a 5.707" center-to-center distance. The 198 engine has the longest rod with a center-to-center distance of 7.006" and is PN 2951262. The 225 rod (PN 2406657) has a center-to-center distance of 6.699".
The 225 cast crank engine uses a unique connecting rod PN 4041994. The two rods for the 225 are not interchangeable.
K. Rod Bolts and Nuts
All slant six connecting rods use 3/8 bolts and nuts. A hi-strength steel 3/8 bolt P3614521 and nut P3690632 are available for all the slant six connecting rods or obtain the complete package - Bolts & Nuts P4120090.
Rod bearings come in two materials, F-77 Tri-Metal recommended for oval track race cars and long life durability and the softer materials (alum. or babbitt) for drag and other race cars and very high rpm. The recommended main bearings clearance for racing should be 0.002" to 0.003." Includes upper and lower shells.
P4349009 '60-'76, Forged Crank, Babbitt, Std. Size P4349010 '60-'76, Forged Crank, Babbitt, .010 Undersize P4349011 '76-'84, Cast Crank, Babbitt, Std. Size P4349012 '76-'84, Cast Crank, Babbitt, .010 Undersize
All the slant six engines use the same piston. The standard bore size piston is PN 2084384. There are four oversize pistons available in the sizes of .005, .020, .040, and .060. The piston pin is a press-fit in the rod and has a diameter of .9008".
M. Valves and Valve Gear
All the above cylinder heads use the same size valves which are 1.62" diameter on the intake and 1.36" diameter exhaust.
The six cylinder engine has used one valve spring - PN 1739534. The blueprint specs are: 74# @ 1.62" closed; and 150# @ 1.31" open. The valve spring installed height is 1.62". The best valve spring available for higher engine speed operation with high performance camshafts (with cam specs of up to 284 degree duration and .470 lift) is the 340 valve spring - PN 2863439. This spring will increase the valve open load approximately 50-60 pounds. The stock valve spring retainer (PN 2402045) is the same for all sixes but a heavy duty retainer (PN 2202546) is available.
The rocker arms (PN 1947594) are mechanical and have an interference screw valve lash adjustment. The tappets (PN 2469501) are mechanical and the same in all engines.
The 198 and 225 engines share the same pushrod (PN 2120514), while the 170 uses a shorter pushrod (PN 1947704).
The '81 -'82 slant six uses a hydraulic camshaft and a resulting valve gear are unique to this package. The hydraulic tappet is PN 4106028 while the pushrod (PN 4173482), rocker arm (PN 4173909) and rocker shaft (PN 4100397) are also special to this package.
See a later section on race valve train components.
The '82-'82 slant six uses a hydraulic camshaft and a resulting valve gear that are unique to this package. The hydraulic tappet is PN 4106028 while the pushrod (PN 4173482), rocker arm (PN 4173909) and rocker shaft (PN 4100397) are also special to this package.
See a later section on race valve train components.
N. Intake Manifold
The slant six has been produced with three different manifolds - a one barrel, a two barrel, and a four barrel. The four barrel manifold (PN 2129898) was produced on the 1960-62 engine but is no longer available. There are aluminum four barrel manifolds available for the slant-six from Weiand or Offenhauser. The two barrel manifold (PN 2806816) has been used on the marine six cylinder engine and the export 225 engine. All slant-six intake manifolds are interchangeable.
The "Feather Duster" aluminum one barrel manifold PN 3837608 was introduced in 1975. The new aluminum two barrel manifold PN 4041042 was inIroduced on the 1977 models and is superior to the old -export- manifold mentioned above. See later section on high performance manifolds.
The standard flywheel uses a 9 1/4" clutch unit.
There is a flywheel PN 2863405 which will accept an 11" clutch but requires a different bell housing.
P. Engine oiling
The standard slant six oil pump should be sufficient for most uses. If more oil pressure is desired, the standard oil pressure relief spring can be replaced with a stronger spring PN 2406677 used in the Hemi oil pump. There is also a windage tray PN P3690274 available. See Oiling System Section.
High performance, high output oil pump assembly. Provides a 25% increase in oil volume. Ideal replacement for stock pump in high performance applications. Comes fully assembled with special pickup and ready to install.
P4286740 Hi-Po Oil Pump Assembly.
The standard ignition system on the six cylinder from 1960 to 1972 has been a single point distributor system. The 1973-83 six cylinder engines introduced the new electronic ignition system on the six. The electronic ignition system distributor PN 3755038 or PN 3755045 (2 bbl. engine) will fit any six. (See the next section for the electronic ignition conversion parts, plug wires etc.)
R. Engine Paint
Direct Connection's engine paint matches the factory original colors so you can keep your engine compartment looking authentic. 16 ounces of quick drying enamel included in each can for painting engine blocks, parts or for fast touch up. Choose from six authentic colors. See description below for proper application.
P4120751 Race Hemi Orange - A bright orange color used on cars equipped with Max Wedge engines (413 and 426 Cross Ram) during 1962-64. Also used on 426 race Hemi's built in 1964-65.
P4349216 Street Hemi Orange - A reddish-orange color used on 426 Hemi's built in 1966-71. Commonly referred to as "Hemi Orange." During 1969-71, the high performance 383 and 440 engines and in 1970-7 1, the 340 engines were also painted this color.
P4120753 Black - All 2.2 engines since 1981 and 318 and 360 engines since 1983 have been painted black from the factory.
P4120752 Turquoise - This medium blue-green color was used on all B/RB big blockengines during 1962-71 with the exception of the high performance 383/440 engines, which were painted Street Hemi Orange.
P4349218 Red - This is the bright red color used on all 273 engines from 1964-69. Also, the 1968-69 340 engines and most mid-1960's 318 engines were finished in this color.
P4349217 Blue - This medium blue color was used on all production engines from 1972-83 with exception of the 2.2 engine. Most 318 engines built from the late 1960's through 1972 were painted this color.
Next: Off-Road Modifications
Slant 6 Index