1966-87 Chevrolet & GMC Header Code Number: 003 Installation Instructions
Fits all models with standard and automatic transmissions, power brakes, power steering, air conditioning and transmission safety locks.
1. Prepare the truck for installation.
a. Disconnect the negative cable on the battery.
b. Remove the spark plugs and spark plug shields.
c. Remove the smog manifolds if equipped with a smog air pump.
d. If the generator or alternator is mounted on the left side exhaust manifold, remove the cap screws and move the unit out of the way. It is not necessary to disconnect the wires. If the alternator is mounted to the front of the engine on the right side, it does not have to be removed.
e. If equipped with air conditioning, dismount the compressor but do not disconnect the lines.
f. If equipped with power steering, loosen the tension adjustment nut.
g. Remove the dipstick and dipstick tube if necessary.
h. Jack the truck up at least 24″ and place solid supports under the frame, front and rear.
i. Remove the exhaust manifolds and exhaust pipes.
j. Remove the starter if necessary.
2. Check the condition of the motor mounts.
It is recommended that new motor mounts be installed before installing Headers.
3. Install the left side Header from below.
a. Hold the Header and gasket in position and install the front and rear Header Bolts. Do not tighten.
b. Install the balance of the Header Bolts. Do not tighten.
c. If the generator or alternator was mounted on the left manifold, remove the two front Header Bolts and install the mounting bracket.
d. If equipped with power steering, use one of the original manifolds bolts and cut a piece of spacer material to exact size and install as described below.
Get pdf 1966-87 Chevrolet & GMC Header Code Number: 003 Installation Instructions
