To remove the carbureted models, begin by draining the cooling system, then remove the air cleaner and intake duct assemblies. Carefully mark and detach any emissions control connections at the air cleaner, disconnect the upper radiator hose from the thermostat housing, and disconnect the heater hose and water pump by-pass hose at the intake manifold connections. For a 7.5L engine, remove the right valve cover. Mark and disconnect the spark plug wires at the spark plugs, then remove the distributor cap along with the spark plug wires. Disconnect the primary low voltage wires from the coil, marking them for correct reinstallation, and remove the coil mounting bracket and mounting bolt. Remove the carburetor fuel inlet line from the carburetor, positioning it out of the way, and disconnect the vacuum advance hose(s) from the distributor, marking them for proper installation. Remove the distributor and any wires from sensors mounted in the intake manifold or upper thermostat housing. Remove the accelerator cable or linkage connection at the carburetor, the kickdown cable if equipped with an automatic transmission, and the pull cable and activating unit from the intake manifold if cruise control is present. Remove the vacuum hose leading to the power brake booster from the intake manifold and secure it to the firewall. If servicing the carburetor separately, remove it from the intake manifold, and disconnect the crankcase vent hose leading from the manifold to the valve cover. For fuel-injected models, remove the upper intake manifold, drain the cooling system, and remove the distributor. Label and disconnect all electrical harness connectors from lower intake manifold sensors and solenoids, as well as any vacuum hoses from the lower intake manifold. Relieve the fuel system pressure, disconnect the fuel supply and return lines from the fuel rail, and disconnect the fuel injector electrical connectors. Remove the oxygen sensor ground wire from the intake manifold stud, the upper radiator hose from the thermostat housing, and the bypass and outlet hoses from the intake manifold. Remove the coil/solenoid bracket assembly and position it out of the way. For all engines, remove the bolts retaining the intake manifold to the cylinder heads, attach lifting hooks at opposite corners, and lift the intake manifold from the engine, taking care not to damage the mating surfaces. Clean the mating surfaces of the intake manifold and cylinder heads, remove the end gaskets from the top of the engine block, and remove the oil gallery splash pan if equipped. For installation, reassemble the manifold by reversing the disassembly procedure, applying electrical conductive sealant to the temperature sending unit threads and RTV sealant to the thermostat gasket. Apply a bead of RTV sealant to the mating points at the junctions of the cylinder heads and engine block, position the new manifold end seals carefully, and ensure the intake manifold gaskets are aligned correctly with the cylinder heads. Apply a bead of RTV sealant to the interlocking corners of the intake manifold gasket and end seal, install locating pins if necessary, lower the intake manifold into position, and install the retaining bolts, tightening them in sequence to the specified torque. Reinstall the remaining components in reverse order, refill the cooling system, and start the engine, allowing it to reach operating temperature while checking for leaks and adjusting the ignition timing if necessary.