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Chrysler, one of the most dominant names during the early
“Muscle Car” era, has developed five basic series of engines
which are popular choices in racing, street performance and
towing applications. For our purposes we will refer to the 273-360
Small Block Chrysler engines as the “A” engine and the 383-440
big block standard head engines as the “B” engine. In recent
years, the engineers at Chrysler have introduced three versions of
the V10 engine platform, as well as a new 5.7L & 6.1L Hemi
design. In the following information we have attempted to pass
along some common “tips” learned during our many years of
engine building, as well as the experiences of many of our
customers.We will not attempt to cover all of the little things, only
the more unique and aggravating trouble spots. If ever in doubt,
there are many excellent reference manuals. Mopar Performance
has one of the best. It goes into great detail about Chrysler
engines. Finally, there is the ever present CAM HELP® line at
1-800-999-0853.
Engine Types
Small Block, "A" Uses "20" Prefix
The basic 273-360 engines, produced in the mid 1960’s, have
remained relatively unchanged as far as the valve train is
concerned. The 1964-1991 engines used shaft type rocker arms,
which required some special changes in the camshaft design.
This was to allow oil to flow to the top of the engine and into the
rocker arm shafts. Most of these early engines featured either
grooved or offset holes in the second and fourth cam journals. In
some instances a combination of both grooves and holes were
employed. You must remember that if your engine has
shaft type rocker arms, there must be some groove or
oiling hole combination on the cam journals. In 1992 the
Magnum version of the “A” engine was changed to a pedestal style
individual rocker arm design.
Magnum
The new Magnum engines utilize a pedestal mount rocker arm
system. They come from the factory with a nonadjustable valve
train and have 5/16” bolts fastening the rockers to pedestals on
the heads.
5.7L & 6.1L Hemi, Uses “112” Prefix
In 2003 Chrysler called on the legendary “Hemi” cylinder head
design to begin a new era in Mopar performance. This new engine
has the same familiar perpendicular valve arrangement but does
not share any parts with the classic Hemi engines. Rocker arms
are shaft mounted with 1.6 ratio on intake and exhaust. Two rocker
shafts per head are used, which is similar to the earlier Hemi.
Because of this design, different length intake and exhaust
pushrods are used. The new engine also uses smaller, .842”
diameter hydraulic roller lifters and a single bolt cam sprocket. |
There are concerns when installing aftermarket camshafts in
these engines. The factory piston has a dome and no valve reliefs.
Extra caution should be taken to ensure adequate piston to valve
clearance. It is also necessary to deactivate the MDS (multiple
displacement system) when installing and using a performance
camshaft. Computer tuning must be performed to enhance
drivability.
V10, Uses “97” and “111” Prefixes (Viper)
We have two different cores for this engine, depending on the
year model. The 2002 and older blocks use a single bolt core, and
the 2003 and later cores are a 3-bolt design.
Big Block “B” or “RB”, Uses “21” and “23” Prefixes
The “B” and “RB” engines used two different deck height blocks.
They require different length pushrods, so when considering
pushrod length, remember that the 383-400 engines use a shorter
pushrod than the 413-440 engines. The larger engines with the
taller blocks use a pushrod that is approximately 3/4” longer than
the other.
When converting either of these engines to adjustable rocker
arms, you must also replace the pushrods. The standard pushrod
used with nonadjustable rocker arms uses a pushrod with a ball on
each end. COMP Cams® aluminum roller rocker arms use a
pushrod with a ball on the lifter end and a cup on the rocker arm
end. The new COMP Cams® Pro Magnum Rocker Arm™ Kit for these
engines uses a ball-ball pushrod like the standard setup, but the
length is different. In either case, the correct pushrods must be
used for the rocker arm type selected.
Hemi, Uses “24” and “26” Prefixes
There are two basic factory versions of the original Hemi engine.
The most common is the 426 Hemi, which was introduced in 1964.
It uses the “24” prefix. Derivatives of this engine can be found in
almost all Alcohol and Fuel cars racing today. One of the most popular
drag racing engines, it is easily recognized by the distributor
location, which is in the front of the block. As far as production
engines are concerned, most of the parts are interchangeable.
Hybrid Hemis; however, have relatively few interchangeable parts
because most are custom made.
The old style 301-392 Hemi engine, which uses the “26” prefix,
is most readily recognized by the location of the distributor at the
rear of the block. There were several versions of this engine;
therefore, it is highly recommended that before ordering any
parts you make sure exactly which engine you are working on.
These engines were very popular in the 60’s and 70’s and can
still be found in many street machines and street rods, but they
are becoming very hard to maintain due to the lack of replacement
parts. |
