REMOVAL & INSTALLATION
6 Cylinder Engines
All six-cylinder engines used feature an intake manifold which is an integral part of the cylinder head and, therefore, cannot be removed.260, 289, 302 (except Boss), 351 W, 390, 427, 428, and 429 SCJ Engines
See Figures 1 through 15
- Drain the cooling system.
- Disconnect the upper radiator hose from the thermostat housing and the bypass hose from the manifold.
- Remove the air cleaner and ducts.
- Remove the distributor cap and wires from the engine. Mark the position of the distributor rotor in relationship to the intake manifold, remove the primary wire from the coil, then remove the distributor hold-down bolt and the distributor.
- Remove all vacuum lines from the intake manifold and remove the temperature sending unit wire.
- Disconnect the fuel line and any vacuum lines from the carburetor.
- Remove the coil.
- Remove all carburetor linkage and kick-down linkage that attaches to the intake manifold.
- On 390, 427, and 428 engines, remove the valve covers, the rocker arm assemblies, and the pushrods. The rocker arms should be removed by backing off each of the four bolts two turns in sequence from front to back. Keep the pushrods in order so that they can be installed in their original position.
- Remove the manifold attaching bolts and remove the manifold. If it is necessary to pry the manifold to loosen it from the engine, use care not to damage any gasket sealing surfaces.
- Clean all gasket surfaces and firmly cement new gaskets in place. The gaskets should be securely locked in place before attempting to install the manifold.
- Reverse the above procedures to reinstall. On 390, 427, and 428 engines, refer to the procedures for Valve Lash Adjustment, found at the end of the Cylinder Head, information.
- Tighten the intake manifold bolts in sequence, and to the specifications listed in the Torque Specifications chart.
See Figures 16 and 17
- Drain the cooling system and remove the air cleaner. On the Boss 302 engine, disconnect the Thermactor air hose from the check valve at the rear of the intake manifold and loosen the hose clamp at the hose bracket. Remove the air hose and Thermactor air bypass valve from the bracket and position it out of the way.
- Disconnect the accelerator linkage and accelerator downshift linkage, if so equipped, and position it out of the way. On the Boss 302, disconnect the choke cable from the carburetor.
- Disconnect the high-tension lead and wires from the coil. Disconnect the engine wire loom and move it out of the way.
- Disconnect the spark plug wires from the spark plugs by grasping, twisting, and pulling, molded cap only. Remove the distributor cap and wire assembly.
- Remove the carburetor fuel inlet line.
- Disconnect the distributor vacuum hoses from the distributor. Remove the hold-down bolt and the distributor.
- Disconnect the radiator upper hose from the coolant outlet housing and disconnect the temperature sender wire.
- Loosen the clamp on the water pump bypass hose at the coolant outlet housing and slide the hose off the outlet housing.
- Disconnect the crankcase vent hose (PCV) at the rocker cover.
- If the vehicle is air-conditioned, remove the compressor-to-intake manifold brackets.
- Remove the intake manifold and carburetor as an assembly. Discard all used gaskets and clean all mating surfaces.
- Reverse the procedure for installation.
- Torque the intake manifold retaining bolts in sequence to the specifications listed in the Torque Specifications table.
See Figure 18
- Disconnect the battery.
- Drain the cooling system.
- Disconnect the heater hose from the manifold.
- Disconnect the positive crankcase ventilation (PCV) hose from the righthand rocker cover. Disconnect and tag all vacuum lines from the rear of the intake manifold.
- Twist and pull the molded spark plug wire cap from each plug. Remove the plug wires from the brackets on the rocker covers.
- Disconnect the high-tension lead from the coil and remove the distributor cap and wires from the distributor as an assembly.
- Disconnect the accelerator linkage from the carburetor. Remove the bolts that attach the accelerator linkage bellcrank. Disconnect the linkage spring and position the linkage to one side.
- Disconnect all distributor vacuum lines from the carburetor and vacuum control valves, and tag them.
- Disconnect the carburetor fuel line.
- Disconnect the wiring harness from the coil battery terminal, temperature sender unit, oil pressure sending unit, and other connections, as necessary. Disengage the wiring harness from the retaining clips at the left rocker cover bolts. Move the harness out of the way.
- Disconnect the Thermactor air bypass valve from the mounting bracket and place it to one side.
- Remove the coil and bracket assembly.
- Disconnect the manifold heat inlet and outlet tubes from the rear of the manifold and from the exhaust pipe.
- Remove the distributor from the engine.
- Remove the intake manifold attaching bolts.
- Remove the manifold and carburetor as an assembly. Discard used gaskets.
- To install the intake manifold, reverse the above procedure-the manifold should be tightened in place as shown in the illustration.