PerTronix D381 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: D381

1965 – 1982 Corvette 396-502 Big Block

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

NOTE: These headers require the purchase of the side pipes (#D930, D930-C, or D930B)
and mufflers (D950, D951, or D952). If your alternator/generator is mounted to the exhaust
manifold you will need to purchase bracket #H7606. 1965-82 A/C models need A/C
bracket #H7608. These headers do not accommodate smog air injection tubes, if you are

retaining an air pump with injection tubes, these headers will NOT work.

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.

3. Unbolt the stock Headpipes from the manifolds and remove the pipes and mufflers from
the car.

4. Remove the A/C compressor if mounted to Right side manifold, Spark Plug wires and
Spark plugs, Clutch Z Bar (if manual transmission)

5. Remove the stock Exhaust manifolds or existing headers.

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6. Remove the rocker arm panel molding. The rocker panel will need to be modified as
shown in the illustrations. Due to variances in cars and years, we recommend that the
illustration only be used as a guide – check fit parts before cutting or trimming.

INSTALLATION

DRIVER SIDE

1) Starting from below, slip the driver’s side header up into position. Slip the gasket between
the head and the header and start all the header bolts but do not tighten at this time.

2) Install the muffler insert into the sidepipe. Install the rubber bushing into the tab bracket
on the sidepipe. Slip the sidepipe onto the header collector. Check the position of the
sidepipe brackets to the holes in the rocker panel. Trim the rocker panel as necessary.
Due to Chevrolet manufacturing tolerances, it MAY be necessary to slot the holes in the
sidepipe brackets in order for the sidepipe to slide completely onto the collector. This is
not usually required.

3) Insert the ‘T’ bolt into the hole in the rocker panel. The rubber bushing will slide over the
bolts and is secured with the flat washer and nut.

4) Tighten the header flange bolts, side pipe tab bolts and the pinch bolt on the front of the
side pipe (to collector).

PASSENGER SIDE

1) From below, slip the passenger side header up into position. Slip the gasket between the
head and the header and start all the header bolts but do not tighten at this time.

2) If equipped with Air Conditioning modify the bracket as shown in the illustration.

3) Install the muffler insert into the sidepipe. Install the rubber bushing into the tab bracket
on the sidepipe. Slip the sidepipe onto the header collector. Check the position of the
sidepipe brackets to the holes in the rocker panel. Trim the rocker panel as necessary.
Due to Chevrolet manufacturing tolerances, it MAY be necessary to slot the holes in the
sidepipe brackets in order for the sidepipe to slide completely onto the collector. This is
not usually required.

4) Insert the ‘T’ bolt into the hole in the rocker panel. The rubber bushing will slide over the
bolts and is secured with the flat washer and nut.

5) Tighten the header flange bolts, side pipe tab bolts and the pinch bolt on the front of the
side pipe (to collector).

6) Reinstall the Clutch Z bar, Spark plugs and wires, and A/C compressor.

7) Check all brake and fuel lines for clearance around headers and exhaust and relocate as
necessary.

8) Connect the negative battery cable.

9) Start the car and check for leaks

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.

Double-check the tightness of all bolts including brackets and accessories.

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STARTING THE ENGINE

A/C Bracket Modification ~ Cut shaded area

1963-67 Rocker modification

1967-82 Rocker modification

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.

PARTS LIST

Qty Description

1 Left side header
1 Right side header
2 Header gaskets
12 3/8 X 1“, header bolts
12 Lock-washer
2 Doug’s Stickers

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