Chevrolet Full-size Cars 1968-1978 Repair Guide

Exhaust Manifold

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REMOVAL & INSTALLATION



Inline 6-Cylinder Gasoline Engine
1968-74 VEHICLES

Exhaust manifold removal for these model years is covered in the Intake Manifold, Removal and Installation section earlier in this information.

1975-78 VEHICLES


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Fig. Fig. 1 Inline six-cylinder engine exhaust manifold torque sequence-1975-78 vehicles

  1. Disconnect the negative battery cable. Remove air cleaner.
  2.  
  3. Remove the power steering and/or AIR pumps and brackets, where they are present. (You need not disconnect power steering hoses-just support the pump out of the way.
  4.  
  5. Working from below, with the vehicle safely supported, disconnect the exhaust pipe at the manifold and at the catalytic converter bracket near the transmission mount. If the vehicle uses an exhaust manifold mounted converter, disconnect the pipe at the bottom of the converter and remove the converter.
  6.  
  7. Working from above, remove the rear heat shield and accelerator cable bracket.
  8.  
  9. Remove the exhaust manifold bolts, and pull off the manifold.
  10.  

To install:

  1. If the manifold is to be replaced, transfer the EFE valve, actuator, and rod assembly to the new part.
  2.  
  3. Clean and then inspect the manifold carefully for cracks, and for free operation of the EFE valve. Repair or replace parts, and free up the EFE valve with solvent, if necessary.
  4.  
  5. Make sure the gasket surface is clean and free of deep scratches. Position a new gasket on the manifold, and then put the manifold in position on the block, and install the bolts hand-tight.
  6.  
  7. Torque all bolts in the proper order to the specified torque (see illustration).
  8.  
  9. Install the rear heat shield and the accelerator cable bracket.
  10.  
  11. Working from underneath, connect the exhaust pipe at the manifold flange and connect the converter bracket at the transmission mount. If the vehicle has an exhaust manifold converter, first install the converter to the manifold loosely; then attach the exhaust pipe to the converter and align the exhaust system; finally, torque the converter mounting bolts to 15 ft. lbs., in an X pattern, and torquing in several stages.
  12.  
  13. Working from above, install the power steering and A.I.R. pumps as necessary. Then, install the air cleaner and connect the battery ground cable.
  14.  

V8 Engines
1968-78 VEHICLES


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Fig. Fig. 2 Exploded view of the small block Chevrolet engine exhaust manifold mounting



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Fig. Fig. 3 Bend the locktabs up and off of the bolt heads



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Fig. Fig. 4 Remove the exhaust manifold attaching bolts



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Fig. Fig. 5 Loosen the spark plug heat shield hold-down screws. Pull up and out on the shield to remove



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Fig. Fig. 6 From underneath, unbolt the exhaust pipe from the manifold then remove the exhaust manifold

  1. Disconnect the negative battery cable.
  2.  
  3. If equipped with AIR (Air Injection Reaction), remove the air injector manifold assembly. The 1 / 4 in. pipe threads in the manifold are straight threads. Do not use a 1 / 4 in. tapered pipe tap to clean the threads.
  4.  
  5. If applicable, remove the air cleaner preheater shroud.
  6.  
  7. Remove the spark plug wire heat shields. On Mark IV engine, remove spark plugs.
  8.  
  9. On the left exhaust manifold, disconnect and remove the alternator.
  10.  
  11. Disconnect the exhaust pipe from the manifold and hang it from the frame out of the way.
  12.  
  13. Bend the locktabs and remove the end bolts, then the center bolts. Remove the manifold.
  14.  

A 9 / 16 in. thin wall 6-point socket, sharpened at the leading edge and tapped onto the head of the bolt, simplified bending the locktabs. When installing a new manifold on the right side on 1978 V8s you must transfer the heat stove from the old manifold to the new one.

  1. Position the manifold and install the end bolts, then the center bolts. Bend the locktabs.
  2.  
  3. Connect the exhaust pipe at the manifold.
  4.  
  5. On the left exhaust manifold, install the alternator.
  6.  
  7. Install the spark plug wire heat shields. On Mark IV engine, install spark plugs.
  8.  
  9. If applicable, install the air cleaner preheater shroud.
  10.  
  11. If equipped with AIR (Air Injection Reaction), install the air injector manifold assembly.
  12.  
  13. Connect the negative battery cable.
  14.  

 
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