 |
| Non cross drilled style |
The other style head gasket is the
cross drilled style, Mopar part number 5281065.
This is the same style as the Mopar Performance P4452006 head gasket. Unlike the stock gasket, the Mopar
Performance part features double cross drilled ports. Notice in the below illustration how there is
only one set of cross drilled holes (highlighted green) between the cylinders. The Mopar Performance gasket will have
another set of matching holes towards the front of the block. No production vehicles came equipped with
double cross drilled blocks. This style
gasket blocks off the steam ports to force coolant through the cross drilled
ports to increase head gasket life by lowering head gasket temperature between
the cylinder bores. This gasket should
not be used with a non cross drilled block because of potential cooling issues. The Mopar Performance
P4452006 head gasket has been superseded to part number P4452006AB. It lists for $92.85.
 |
| Cross drilled style |
The last style of gasket worth mentioning is offered in the
aftermarket. It features open steam
ports and double cross drilled ports. When
used in a cross drilled block, instead of most of the coolant flowing through the warmer cross drilled ports, they
are divided among both the steam ports and cross drilled ports. This may cause higher head gasket temperatures
in a cross drilled block.
 |
| Aftermarket style |
Below is a list of head gasket part numbers for each year
and engine combo. Part numbers
highlighted in blue have been superseded to part number 5281064, non cross
drilled style. Part numbers highlighted
in red have been superseded to part number 5281065, cross drilled style.
SOHC--Head Gasket Part Numbers
|
|||||
2.2
|
2.2 T1
|
2.2 T2
|
2.5
|
2.5 T
|
|
1985
|
4105468
|
||||
1986
|
4387319
|
4387319
|
4387319
|
||
1987
|
4387319
|
4448301
|
4387837
|
4387319
|
|
1988
|
4448301
|
4448736
|
4448302
|
4448301
|
|
1989
|
4448301
|
4448302
|
4448301
|
4448302
|
|
1990
|
4448301
|
4448302
|
4448301
|
4448302
|
|
1991
|
5281064
|
5281064
|
5281065
|
||
1992
|
5281064
|
5281064
|
5281065
|
||
1993
|
5281064
|
5281064
|
5281065
|
||
1994
|
5281065
|
5281065
|
|||
1995
|
5281065
|
||||
Of interesting note is the application of the non cross
drilled head gasket throughout the 1990s. Many online sources indicate cross drilled naturally aspirated blocks
existed as early as 1990. The factory
parts manual disagree, showing non cross drilled head gaskets were still in use
as of the 1993 model year. The factory
service manual of the same model year contradicts this by omitting the
illustration of the non cross drilled gasket, showing only the cross drilled
gasket was available.
This contradicts the popular notion that "late
1990-1995" naturally aspirated blocks were cross drilled.
It seems 1993 may have been the cross over year for
naturally aspirated blocks.
Additionally, the factory parts manual lists the wrong
application of the cross drilled head gasket in 1987. The above chart has been corrected to show
that 1987 "EDR" code engines use head gasket part number 4387837.
Opinions / Observations
The following is a collection of opinions and observations
on what is preferred in a head gasket.
Conjoined Fire Rings
 |
| Non conjoined fire ring |
 |
| Conjoined fire ring |
Many prefer conjoined fire rings over non conjoined fire rings.
Cross Drilled or Non Cross Drilled
Dave Zelkowski, a former Chrysler Engineer involved in the
development of the 1980s Turbo Dodges, states "The purpose of cross
drilling is to reduce the temperature of the head gasket between the cylinder
bores." Based on comparing the two
styles of factory gaskets, it seems that the non cross drilled style head
gasket allows coolant to pass through the steam ports while the cross drilled
style head gasket blocks those steam ports to force coolant to pass through the
cross drilled ports.
In the aftermarket, one common feature is for the head
gasket to have both cross drilled ports and steam ports open. This gasket is acceptable for use in both
cross drilled and non cross drilled blocks.
In cross drilled blocks, however, any cooling advantages that the
factory intended are lost. This may lead
to the unexpected failure of such a gasket in a cross drilled application.
Mixing and Matching
If you have a vehicle that uses different heads or blocks
than factory, use the below guide as a suggestion as to what gasket style is
preferred.
Head
|
Block
|
Suggested Head Gasket
|
Cross drilled
|
Cross drilled
|
P4452006
|
Cross drilled
|
Non cross drilled
|
5281064AB
|
Non cross drilled
|
Cross drilled
|
5281064AB
|
Non cross drilled
|
Non cross drilled
|
5281064AB
|
Unknown
|
Unknown
|
Aftermarket
|
Special Notes
This guide is only a guide.
It is based on the factory service manual, factory parts manual, and
limited firsthand experience. It
excludes many of the special head/block combinations found on Shelby L body
vehicles. Those vehicles got some crazy
weird combos that sometimes required head gaskets not mentioned above. It also excludes much information about
double cross drilled applications found in limited production / prototype
vehicles.
