If the engine has been removed from the car, disregard the following steps which do not apply. For vehicles equipped with air conditioning, carefully examine the routing of the NC hoses and the mounting of the compressor; depending on the system, it may be possible to remove the intake manifold without disconnecting the A/C system. If uncertain, consult a certified dealer or refrigeration specialist to have the system depressurized, and never disconnect the A/C hoses while under pressure. Begin by disconnecting the negative battery cable, draining the coolant from the radiator, and removing the air cleaner assembly. Next, disconnect the upper radiator hose, heater hose from the intake manifold, and the small by-pass hose from the water outlet on Olds engines. Disconnect the accelerator linkage at the carburetor, ensuring any supporting bracket is also removed. With a container ready to catch spillage, disconnect the fuel inlet hose at the carburetor, plugging the end to prevent dirt entry and excessive fuel seepage. Disconnect all other hoses connected to the carburetor, identifying each with numbered tape to avoid confusion during reassembly. For Chevrolet-manufactured engines, remove the distributor and secure the distributor cap with spark plug wires against the firewall. If equipped with an external coil from 1970 to 1974, disconnect the wiring at the top of the coil, marking each wire for reassembly. Disconnect the vacuum hose leading to the power brake booster if applicable, remove the upper bracket for the alternator if attached to the manifold, and remove the air conditioning compressor bracket at the intake manifold. Remove the intake manifold-to-cylinder head attaching bolts, counting to ensure all 12 bolts are removed, then lift the manifold with the carburetor free from the engine without prying on mating surfaces. If replacing the intake manifold, transfer applicable accessories such as the carburetor, temperature or oil pressure sending unit, water outlet and thermostat with a new gasket, heater hose and water pump hose adapter fittings, EGR valve with a new gasket, emission system TVS switches, carburetor choke assembly, and ignition coil and bracket for 1970 to 1974 models. Before installing the manifold, place clean lint-free rags in the engine cavity and thoroughly clean the engine block, cylinder heads, and manifold gasket surfaces, removing all extra gasket material and sealing compound. Install new front and rear seals to the engine block using RTV or an equivalent sealant, extending the bead about ½ inch up the sides of each cylinder head to seal the side gaskets. Position new manifold side gaskets on each cylinder head, using sealant around the water passages and ensuring proper mating with the front and rear seals. Lower the intake manifold into position carefully, attach the small by-pass hose to the water pump, and for Oldsmobile-manufactured engines, dip each bolt in clean engine oil before torquing the attaching bolts to specifications in the correct order. Finally, install the remaining components in reverse order of removal, fill the radiator with coolant, start the engine, and check for leaks, adjusting the ignition timing and carburetor idle speed as necessary.
Posted by GMPartsGiant Specialist 
