Product Description
Sonderpreis, gilt nur für Restlagerware!
Big Port Commando Cylinder Head
Small block performance cylinder head, featuring stock intake bolt pattern for standard manifold, and dual-drilled exhaust pattern for production or W2 exhaust. Utilizes W2/W5 type offset intake rockers allowing unrestricted port cross section from the intake flange to the valve. Intake has an easy flow potential of over 300 cfm with seat and chamber machining and minor porting, making it the best value in small block power potential. Offset rocker allows for the cross sectional area to take power to the next level, far beyond the capabilities of standard layout heads. Compatible with standard intake and exhaust, the Big Port Commando is the low-cost alternative for exotic _race style _ heads.
Die Köpfe sollten vor den Zusammenbau entgratet und gereinigt werden. Auch die Ventilsitze sollten eingeschliffen werden.
Passende Ventile sind:
-large rectagular ports
-50cc chamber volume
-188cc intake runners
-59° Tappet style
-2,020_/1,600_ Valves
-3/8_ Valve shafts
-standart LA-engine Intake screws
-5 bolt valve cover
-needs W2 type rockers
-casting #4532795
flow:
Intake
.200=116
.300=166
.400=213
.500=250
.600=263
.700=273
.800=280
Exhaust
.200=084
.300=115
.400=141
.500=163
.600=177
.700=187
.800=188
Applications: 1967-‘91 318, 1968-’73 340, and 1971-’92 360 V8 engines and Commando crate motors built up to 1993 (does not fit 1992 & up 5.2L and 1993 & up 5.9L Magnum engines and Magnum crate motors).
Contents: one fully machined aluminum large port Commando cylinder head (bare machined head sold individually).
Specifications:
These heads feature larger intake ports for more airflow. The intake ports flow approximately 268 cfm. The combustion chamber is approximately 50 cc in size. The intake port volume is approximately 188cc and the exhaust port volume is approximately 68cc. The head is designed to use standard length ‘68-’71 340 valves w/ 2.02” intake and 1.60” exhaust. These heads are designed to work with standard 340/360 intake & exhaust manifolds, valve springs, keepers, retainers, “A” engine 5 bolt valve covers, and gaskets. The heads are made w/o any heat crossover passages.
Special Notes:
These heads have special machining thatallows the use of a stock “A” engine style intake manifold. The larger intake ports require the use of offset rocker arms to clear the ports. This situation causes the pushords to be very close to the tapped holes for the intake manifold screws. You can see a small portion of the pushrod hole inside the tapped intake screw holes in the head. This hole looks funny, but should not cause any problems since the pushrod itself will not hit the intake screw. It is recommended that a small about of sealant be applied to each intake screw to minimize the possibility of an oil leak in this area. The benefit of this design is that you can have the larger intake ports and use a stock style intake manifold. All other large port cylinder heads require the use of special intake manifolds. The valve cover gaskets will require minor trimming so that they do not rub on the pushrods.
Valve Springs and Spring Mounting Cups: The spring seats on this head are machined to work with a .100_ thick spring cup. A spring cup or shim must always be used on any aluminum head so that the valve spring does not damage the aluminum spring seat area on the head. The spring mounting cup should have an OD of 1.65”.
Standard “A” engine valve springs will work well with this head. The recommended springs are listed below:
Part number Lift Range Design Retainer Installed height
P4120249 .430”/.500” Single w/ damper P4452033 1.67”/1.70”
P5249847 .480”/.535” Single w/ damper P4452033 1.68”/1.70”
P3412068 .520”/.620” Dual w/ damper P4452033 1.68”/1.70”
Rocker Arms: The larger intake ports on this head require the use of rocker arms with more offset so that the pushrods will clear the ports. These heads are designed to work with W2 Econo rocker arms and rocker shafts (Mopar part numbers P4876343). Standard “A” engine rocker arms / rocker shafts will not fit or work with this cylinder head. The rocker arm pedestals are cast into the head, so rocker stands are not needed. The use of any other rocker shafts may not provide proper oiling of the rocker arms.
Installation Parts (available separately): A few special parts are required when using this cylinder head:
1) The suggested valve part numbers are P5249185 - intake and P5249187 - exhaust.
2) Use Magnum head bolt set part numberP4876759 w/ washer set P4120459. These head bolts are a different length than standard “A” engine pieces. These longer bolts are need to provide room for the larger intake ports.
3) Use W2 Econo Rocker arms & rocker shaft kit P4876343. Ten 3/8”-16 bolts are needed for mounting the rocker shafts (use grade 8 bolts). Use (8) 3/8-16 x 1.5” long and (2) 3/8-16x1.75” long bolts (use grade 8 bolts). The longer bolts are used in the holes that supply oil to the rocker shafts.
4) Use T/A style pushrods with a cup on the top similar to p/n P4529556 w/ approximately 7.23” length. Measure the exact length required for your application since this may be different due to machining of the heads, block, gasket thickness or other factors.
5) Use valve seal package P3690963.
Mopar tested this head using the parts listed above (and w/ a .509” lift camshaft). The use of different component parts may require modifications to the head for pushrod clearance.
Measure and check your compression ratio and valve clearancewhen building your engine.
Consult the Mopar service manual for the proper procedure to remove and replace the cylinder heads.
