PerTronix D627-R User Manual

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

HEADER INSTALLATION INSTRUCTIONS

PART NUMBER: D627 & D627-R

1967-70 Ford Mustang/Mercury Cougar

FE390-428

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!
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

IMPORTANT!

These headers were designed on the original Factory Cobra Jet Super Stock Race Cars
of Paul Harvey and Hubert Platt. They are an extremely tight fit, especially between the
shock towers. Shock towers that have been reinforced make matters worse and may
require slight notching of the reinforcement plates. These headers feature two primary
tubes that crossover under the oil pan for increased performance and fit. Please take
your time when installing as patience is definitely required. Look at the photos for
possible interference and close fit areas before starting. It is not unusual on this type of
Racing header to have to make small flat spots in the tubes and or shim the motor
mounts for adequate clearances. Many factors can affect header fitment including old,
worn or bent motor mounts, previous chassis damage, modified structures, etc. For
period correct look cut all pipes apart at the flanges just past the bolt holes creating 8
pipes at the head, cut the gaskets to match.

DISASSEMBLY

1. Disconnect the negative battery cable from the battery.

2. If a car lift is not available, raise the vehicle 3 feet or higher and support with adequate
safety stands. Make sure the vehicle is on a flat solid surface and is stable.

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3. Remove bolts attaching stock manifolds to the head pipes.

4. Remove spark plug wires and spark plugs.

5. Remove the Oil Filter.

6. Remove the manifold bolts from each manifold.

7. Remove the manifolds or old headers from the car.

8. 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.

INSTALLATION

1. The #1 header tube on each side has a two bolt connector and the header flange has
been cut almost all the way through. We have done this to ease installation. In some
applications it is easier to cut the flange the remainder of the way and separate these
tubes to be installed individually.

2. The #4 header tube, which is the cross over is also cut almost all the way through at the
flange. These should be cut at the flange to separate and ease installation.

3. Once the header flanges have been cut, ease the main header into position from below.
This is a VERY tight fit and needs to be finessed in order to install. We recommend
removing the motor mounts and supporting the motor from below to allow the header to
slip into place.

4. Once you have the main header in place, insert the header gasket and install a couple
of bolts to support the header. We have included two header bolt lengths to help with
tight fitments. Repeat for the opposite side.

5. The # 1 tube (if removed) and the #4 tube on each side can now be fed into place and
bolted to their respective 2 bolt connector flanges and to the cylinder head.

6. Install all remaining bolts, with lock washers, and tighten evenly.

7. Reinstall motor mounts and double check clearances.

8. Reinstall spark plugs and wires, oil filter, and re-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.

STARTING THE ENGINE

Start the engine and allow it to warm up to operating temperature. Check for any unusual
noises or exhaust leaks. If every thing is OK, stop the engine and tighten all bolts while
the engine is still warm.
NOTE: Check the bolts periodically to make sure they have not loosened. Re-tighten
after the first 500 miles and then again at 1000 miles.

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