Doug S Headers D626 Full Length Header Instruction Manual

D626 Full Length Header

Product Information

This product is a set of headers designed for a 1967-1970 Ford
Mustang or Cougar with a 390-428 engine. Please note that it
requires the Power Steering Bracket P/N H7609 for installation.
These headers will not fit Cobra Jet models with long tube
headers.

Below are the disassembly and assembly instructions for
installing the headers:

Disassembly

1. Loosen the header bolts.
2. Replace the clutch linkage.
3. Start all the header bolts (starting with the most restricted)
   and tighten them evenly.
4. Replace both halves of the motor mounts, lower the engine, and
   replace the center bolt in the mount.
5. If you have an automatic transmission model and the L-3 tube
   contacts the bellhousing between its 3rd and 4th bends, re-form it
   for clearance.
6. Do not reinstall the power steering ram or idler arm until the
   right side is installed.

Assembly – Right Side

1. Remove the stock exhaust manifold and starter.
2. Remove the center bolt from the motor mount and raise the
   engine about 2 inches.
3. Ensure that the headers are properly aligned with the frame by
   adjusting the position of the bolts or using washers under the bolt
   heads.
4. Bolt the supplied reducers to the collectors.
5. Cut the existing headpipes to length and weld the reducers to
   them.
6. Connect the negative battery cable.

Parts List

Installation Instructions & Warranty Information D626 ~ 67-70 FORD MUSTANG & COUGAR, 390-428 NOTE: Requires Power Steering Bracket P/N H7609
NOTE: Will not fit Cobra Jet models Long Tube Headers
REV. 6 5-9-22 DSL

DISASSEMBLY / ASSEMBLY
LEFT SIDE: 1. Unbolt the headpipes (both sides) from exhaust manifolds and mufflers and remove. 2. Remove the power steering ram from the frame. 3. Unbolt the idler arm from the frame. 4. Remove the clutch linkage and center bolt from the motor mount. 5. Jack up the engine about 2 inches. Be sure to use a board between the pan and jack. 6. Remove both halves of the motor mount. 7. Remove the stock exhaust manifold. 8. Clean the head surface of any carbon deposits or other foreign material. 9. Apply anti-seize to the supplied header bolts. 10. Starting from below, work the header up through the chassis into position over the exhaust
ports. 11. With the header loose, replace the clutch linkage. 12. Start all the header bolts (most restricted first) and tighten evenly. 13. Replace both halves of the motor mounts, lower the engine and replace the center bolt in the
mount. Note: On AUTOMATIC TRANS MODELS: If the L-3 tube contacts the bellhousing between its 3rd and 4th bends, re-form for clearance (See Illustration). 14. Do not reinstall the power steering ram or idler arm until the right side is installed.
RIGHT SIDE: 1. Remove the stock exhaust manifold and starter. 2. Remove the center bolt from the motor mount and raise the engine about 2″. Be sure to use a
board between the pan and jack. 3. Clean the head surface of any carbon deposits or other foreign material. 4. Apply anti-seize to the supplied header bolts. 5. Starting from below, work the header up through the chassis into position. 6. With the header loose, reinstall the starter. 7. Start all the header bolts (most restricted first) and tighten evenly. 8. Lower the motor and replace the center bolt in the motor mount. 9. Replace the power steering ram with the purchased H7609 Power Steering Bracket. 10. Reinstall the idler arm. If the idler arm bolts contact the header tubes, either cut off the ends
of the bolts or use washers (under the bolt heads) to shim the bolts further toward the outside of the frame. 11. Bolt the supplied reducers to the collectors. Cut the existing headpipes to length and weld the reducers to them. 12. Connect the negative battery cable.

PARTS LIST:

1 Left side header

1

2 Header gasket

2

32 Bolt, header, flanged, 3/8″-16 x 1″ 38

6 Hex head cap screw, 3/8″-16 x 1-1/4″ 6

Right side header Reducer gasket Lock-washer, 3/8″ Nut, hex, 3/8″-16