PerTronix D6670 User Manual

Corporate Office: PerTronix Inc. 440 E. Arrow Highway, San Dimas, California 91773 * Phone [phone] * FAX [phone] * www.dougsheaders.com

Note: The installation of this header requires that you use a factory
dual hump transmission crossmember from 1986-1989 Mustang 5.0
GT and LX

HEADER INSTALLATION INSTRUCTIONS

D6670

1979-1993 FORD Mustang, 255-302W

PerTronix©

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. Most installations require some
welding. If you are uncomfortable with welding operations, we recommend that you contact a professional exhaust system specialist
to install your new headers.

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 to

DISASSEMBLY

1. Disconnect the negative battery cable from the battery.

2. If a car lift is not available, raise the vehicle 2 feet or higher and support it with adequate safety
stands. Make sure the vehicle is on a flat solid surface and is stable.

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3. Apply penetrating oil to all nuts and bolts to be removed.

4. Unbolt head pipes from stock exhaust manifolds.

5. Remove spark plugs, stock exhaust manifolds, bottom A-arm to frame brace (convertible
models), oil dipstick and tube.

6. Loosen the starter cable so it can be moved for clearance.

7. Replace the spark plugs finger tight so debris will not get into the cylinders while cleaning the
head surface.

8. Clean the cylinder head surface which mates to the header. Use a gasket scraper and wire
brush to make sure that the surface is absolutely clean.

9. After cleaning is complete remove the spark plugs again.

ASSEMBLY

1. Apply anti-seize to all header bolts being used.

2. Apply a THIN film of Ultra Copper Hi-Temp Sensor-Safe Silicone Sealer to the header side of
the 2 supplied gaskets and glue them to the headers. Masking tape can be used to help stick
the gasket to the manifold.

3. Apply a THIN film of Ultra Copper Hi-Temp Sensor-Safe Silicone Sealer to the engine side of
the left side header gasket.

4. If not using the O2 sensors, screw in the provided plugs.

5. Starting from below, work the left side header up into place.

6. Start all of the header bolts for this header but leave header loose.

7. Apply a small amount of THIN film of Ultra Copper Hi-Temp Sensor-Safe Silicone Sealer to the
L-4 slip joint, install it and start those bolts.

8. Tighten all bolts evenly.

9. Apply a THIN film of Ultra Copper Hi-Temp Sensor-Safe Silicone Sealer to the engine side of
the right side header gasket.

10. On the right side, from the bottom, work the R-4 tube into position in front of the starter. Do not
start bolts yet.

11. Work tube R-3 on the outside of R-4, keeping it in front of the starter. Do not start the bolts yet.

12. Hold R-4 to the head at the correct exhaust port and tighten the cable on the starter with it
positioned for maximum clearance.

13. Apply a small amount of THIN film of Ultra Copper Hi-Temp Sensor-Safe Silicone Sealer to the
R-3 and R-4 slip joints.

14. Work the main body of header from the bottom up over the top of the starter. Insert tubes R-3
and R-4 into the slip joints.

15. Start all the bolts.

16. Apply a small amount of THIN film of Ultra Copper Hi-Temp Sensor-Safe Silicone Sealer to the
R-2 slip joint, install it and start the bolts. Torque all bolts evenly.

17. Re-install engine oil dipstick tube and dipstick. Note: It may be necessary to bend the dipstick
tube in order to clear the headers.

18. Tighten the header bolts evenly to a final torque of approximately 25 ft. lbs.

19. Reinstall spark plugs and plug wires.

20. Install reducers and attach exhaust system to reducers.

21. Make sure all of the other fasteners are tightened.

22. Connect the negative battery cable.

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