DOUG S HEADERS D318 4 Tube Header Chevelle Big Block Chevrolet Installation Guide
- June 9, 2024
- DOUG S HEADERS
Table of Contents
DOUG S HEADERS D318 4 Tube Header Chevelle Big Block Chevrolet
Installation Instructions & Warranty Information
D318 ~ 1978-87 Buick Century, Regal, & Wagons 1978-87 Chevrolet Monte Carlo, Chevelle, Malibu, El Camino, & Wagons 1978-87 Pontiac Grand Prix, Le Mans, Grand Am (78-81), Grand Le Mans With Chevrolet 396-502 Big Block Engines Long Tube Headers.
WARNING
This product can expose you to chemicals including Lead, Nickel, Cadmium and
Chromium which are known to the State of California to cause cancer and birth
defects or other reproductive harm. For more information go to
www.P65Warnings.ca.gov
PLEASE READ BEFORE PROCEEDING
Petromax” thanks you for choosing a Doug’s Headers Product. To realize the potential of Doug’s Headers engineering and excellent fit, Please Read and Understand these instructions completely prior to starting the installation. Check that you received all the parts listed on the parts list, if you have any concerns, please contact Petromax before continuing. Headers will have the part number stamped in the flange. Many factors affect he installation of exhaust headers, including worn or aftermarket motor mounts, previous accident damage, aftermarket cylinder heads that may have relocated port or spark plug locations, suspension and steering changes, sagging of original unibody structures due to age. Coating Notes: Coatings can be marred during installation if you are not careful. If you are breaking in a new motor, the extreme heat can alter the appearance of the coating and this is not a warranty issue. We recommend breaking in new motors with stock manifolds or an old set of headers. We use sealing beads on all our headers. The raised bead creates a better seal virtually eliminating leaks if installed properly. It is important to install all header bolts lightly snug and then tighten to factory torque specs stating in the center and working outward. Before starting, allow the vehicle to cool, disconnect the battery, and spray a penetrating oil on all hardware and fittings that will need to be removed. Once you remove your manifold, clean the sealing surface on the head of any old gasket debris or carbon build up.
NOTE:
This is a swap header and is designed to be used with the original Small block
motor mounts and stands. Use of alternative mounts could cause fitment
problems.
Diassembly.
- Remove the Spark Plugs and Wires, Oil filter, Oil Dipstick Tube, Starter, Air Conditioning compressor, and Power Steering Pump if mounted to exhaust manifold.
- Remove the headpoles and catalytic convertors from the stock manifolds and push the pipes out of the way.
- Remove the 8 manifold bolts from each manifold and remove the manifolds.
- Remove the gaskets and any gasket material or any carbon deposits that remain on the head surface.
INSTALLATION
- These headers have one tube on the left side and two tubes on the right that are removable and are a slip fit. They come with the flange not cut completely to help protect the header during shipping. The flange needs to be cut to remove the tubes before attempting installation.
- 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 Driver’s side motor mount bolt and nut. Raise the motor approximately 2”.
- Remove the motor mount and modify as shown in Illustration A, then replace the motor mount.
- With the motor still raised, starting on the driver’s side from below, work the header up into position with the #3 tube removed.
- Slip the gasket into position and start 2 of the supplied header bolts and special lock washers to hold the header in place, leaving them loose.
- From above, slip the #3 tube into position around the steering shaft, sliding the end into the main header and then starting the header bolts. High temp silicone can be used in the slip joint to reduce leaks.
- Lower the motor back into position and reinstall the motor mount bolt and tighten.
- Reinstall the oil filer.
- Tighten all the header bolts evenly, starting from the center outward.
- On Air conditioned models you may have to modify the A/C bracket. Since this is a swap header it will depend on the bracket you are using.
- Cut the Passenger Side Upper A Arm bolt as shown in Illustration B.
- Starting from below, work the passenger side header into position with the #3 & #4 header tubes removed.
- From above, slip the #4 tube into position, sliding the end into the main header. Then slip the #3 tube in to the main header. High temp silicone can be used in the slip joint to reduce leaks.
- With the header still loose, re install the starter motor.
- Slip the gasket between the header and the cylinder head and start all the supplied header bolts and special lock washers. Tighten evenly starting from the center and working outward.
- Reinstall the Spark plugs and wires, the oil dipstick tube, and power steering pump.
- Connect the negative battery cable.
Illustration A: Drivers Side Motor Mount Modification
Illustration B: Passenger Side Upper A Arm Bolt Modification
IMPORTANT CHECK LIST
- Be sure that all brake lines, transmission 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.
START THE ENGINE
Start the engine and allow it to warm up to operating temperature. Check for any unusual noises or exhaust leaks. If everything 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
Parts List
1 Left Side Header
|
1
|
Right Side Header
---|---|---
2| Header Gaskets| 2| 3 ½” Reducers
2| 3 1/2” Reducer Gaskets| 16| 3/8-16 X 1” Header Bolts
22| 3/8” Internal Lock-Washer| 6| 3/8-16 X1 ¼ ‘” Collector Hex Head Bolts
6| 3/8-16 Hex Nuts| 2| Doug’s Stickers
DOUG’S HEADERS LIMITED WARRANTY
All Doug’s Headers and Exhaust products are guaranteed, to the original purchaser, to be free of defects in material and workmanship for one year from date of purchase. This warranty covers the replacement or repair of the product and does not cover the cost of removal and installation, customer applied coatings, or Any discoloration or corrosion of finished surfaces. Damage or product failure resulting from collision, improper installation, off road use, road hazards, the use of exhaust insulating wrap, or rust occurring after installation is not covered by the warranty. This warranty extends only to the original purchaser. Should a part be deemed defective, it should be returned to the original selling retailer and must be accompanied by the sales receipt. If there is no retailer in your area, contact PerTronix direct for a return authorization and return the part prepaid to the factory for inspection. Pertronix reserves the right to replace or repair the alleged defective part and return the part freight collect.