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Corporate Office: PerTronix Inc. 440 E. Arrow Highway, San Dimas, California 91773 * Phone 909.599.5955 * FAX 909.599.6424 * www.dougsheaders.com
HEADER INSTALLATION INSTRUCTIONS
PART NUMBER: D523
1970-74 Pontiac Firebird 326-455
NOTE: These headers will ONLY work with Ram Air II/IV, Super Duty, HO, and Edelbrock
Performer RPM Heads. Some Pontiac Heads do not have bolt holes in the end of the
manifolds. These must be present for the headers to seal properly.
PerTronix©
to realize the full potential of our good fit, please read and understand these instructions completely prior to starting work.
Check to make sure you received the proper parts for your application. The header number will be stamped on the engine
flange. If you are unsure you have received the proper parts call before you start work.
Be sure to work safe! Whenever you work under the vehicle be sure that it is located on level, solid ground and is supported
by adequate safety stands! Remember: Hot asphalt will not support most jack stands!
Many factors affect the installation of headers, some of which are broken or aftermarket motor mounts, accidents that impact the
configuration of the frame, and/or the installation of different engines or aftermarket cylinder heads.
Attention Customers breaking in new engines: Due to the extreme heat generated during the break-in process, the
appearance of the ceramic coating may be altered in certain areas. The protection characteristics and thermal barrier properties
of the coating is never compromised. It is recommended that a cast iron manifold or old set of headers be used for this process.
Notice: The coating of these headers can be marred or scratched during installation. If the header needs to be returned and is
damaged, you will be charged for recoat.
thanks you for choosing
DOUG’S HEADERS
, the best fitting, highest quality header on the market. In order
DISASSEMBLY
1. Disconnect the negative cable from the battery.
2. If a hoist is not available, raise the car 3 feet or higher and support with adequate jack
stands. Make sure the car is on a flat solid surface and is stable.
3. Unbolt the headpipes from the factory manifolds and move the exhaust out of the way.
4. Remove the spark plug wires and spark plugs. Remove the manifolds from the motor.
5. Remove the Oil Filter and Housing, the transmission/key interlocking device, the starter,
and clutch Linkage.
6. If equipped with Air Conditioning, loosen the bracket and slide the compressor out of the
way.
7. Remove the gaskets and any gasket material or any carbon deposits that remain on the
head surface. The use of a gasket removal agent will ease the removal of any gasket
material. Use care not to get debris into ports or spark plug holes.
Part No. 0110-003100 Page 1 of 3 7-15-2009 DSL
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INSTALLATION
1. Place a jack under the oil pan, with a block of wood to prevent damage to the pan.
Loosen the rear transmission mount bolts. Remove the Passenger side motor mount bolt
and nut. Raise the motor approximately 1”. Check that the motor mount to cross member
bolts are installed with the bolt heads on top and the nuts underneath, if not they will
need to be reversed so that the nuts are on the bottom.
2. Starting from below, slide the Passenger side header into position.
3. Lower the motor and replace the motor mount bolt and tighten.
4. Slip the gasket between the header and the head and start all of the supplied header
bolts and special lock washers starting with the 4th one from the front as it has restricted
clearance. Do NOT tighten.
5. With the header loose, install the oil filter housing and the oil filter.
6. Tighten the header bolts starting with the 4th bolt, drawing the header up to the head and
then tightening the remainder of the bolts.
7. On the Driver’s side, check the motor mount to cross member bolts and make sure that
they are installed in the same manner as the passenger side as described above. Cut the
top of the motor mount bolt so that it is flush with the nut.
8. Starting from below, slide the driver’s side header into position.
9. With the header loose in the chassis, reinstall the starter motor.
10. Slip the gasket between the header and the head, install the rear center port bolt (4th bolt
hole from the front) a couple of threads into the cylinder head. Slip the Slotted bolt hole in
the header flange over that bolt; slide the header backwards into place. Start all of the
supplied header bolts and special lock washers starting with the 4th one from the front as
it has restricted clearance.
11. Reinstall the Clutch linkage and Transmission/Key interlock.
12. Tighten the header bolts starting with the 4th bolt, drawing the header up to the head and
then tightening the remainder of the bolts.
13. In order to retain the Hot Air to the carburetor, modify the heat stove as shown in
Illustration 1.
14. Install the supplied reducers using the gaskets and hardware.
15. Cut the headpipes to match the reducers if the original exhaust is to be used.
16. Reinstall the sparkplugs and plug wires.
17. Connect the negative battery cable.
IMPORTANT CHECK LIST
Be sure that all brake lines and fuel lines are clear of headers and/or connector pipes.
All spark plug wires, battery cables, or other electrical components should be clear of
headers and/or connector pipes.
If dipstick tube was removed, make sure it is installed properly and that the dipstick has
been replaced.
Double-check the tightness of all bolts including brackets and accessories.
Part No. 0110-003100 Page 2 of 3 7-15-2009 DSL