JBA 6656SJT User Manual
Corporate Ofce: PerTronix Inc. 440 E. Arrow Highway, San Dimas, California 91773 * Phone 909.599.5955 • FAX 909.599.6424
Installation Instructions
and Warranty Information
For ’67-’70 390/427/428 Mustang
Part# Application Notes
6656S 67-70 Mustang 390 GT 41, 42
6655S 67-70 Mustang 390/427/428/428CJ C6/C4 39, 41, 42
6654S 67-70 Mustang 390/427/428/428CJ 5spd 39, 41, 48, 49, 50
39 Will not t standard 390 cylinder head.Head ange is designed for 14 bolt 390 GT cylinder head only.
41 Fits most rack and pinion conversions.
42 Requires JBA power steering ram drop down bracket for use with factory power steering.
43 Not designed for 5 spd trans applications
48 Fits 5 spd w/aftermarket cross member
49 Will not t factory power steering.Fits manual steering.
50 Fits aluminum Shelby block
WARNING: The product accompanying this document is legal only for off-highway use (except in California or
states that have adopted California emission standards), racing use or for use on pre-emission-controlled motor
vehicles/motor vehicle engines (pre-1966 domestic vehicles certied to California standards, pre-1968 domestic
vehicles certied to federal standards and all pre-1968 foreign vehicles), per the manufacturer’s application guide.
Read all instructions carefully before attempting installation.
Rev. 06/11
PerTronix© thanks you for choosing JBA HEADERS, the best tting, highest quality header on the mar-
ket. In order to realize the full potential of our good t, 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 ange. 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 conguration 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.
JBA uses sealing beads on all its headers. We have found that when installed correctly, the raised bead around
each port increases the pressure exerted on the gasket directly adjacent to the port and effectively prevents leak-
ing gaskets. It is normal for the ange to be raised off the cylinder head the thickness of the sealing bead. It is
important when installing the header, to install all bolts loosely, then tighten evenly to ensure the at installation
of the ange. The torque sequence from one ange to another will vary, but generally every bolt on a header
should be rst t snug, starting from the inside of the ange working out, alternating from top to bottom so
that the bolt connects the ange to the manifold to the point where they barely touch. Second, using the same
inside-out pattern, tighten each bolt until nished. This method will help prevent leakage and will give the user
the best possible performance out of their pair of headers.
Installation of these headers requires an adequate work space, general mechanic’s tools, general mechanical
“know-how” and a reasonable degree of experience. Most auto enthusiasts with these resources will have little
difculty installing these headers. However, you should carefully read these instructions before attempting to
install these headers. If in doubt, consult a professional mechanic. (Better to do it now than to get stuck halfway through the installation.)
1. Place vehicle in a location where the oor is solid and at, with adequate lighting. Do not attempt to work on
a hot engine. Heat causes metal to expand and makes removal of fasteners difcult at best. Disconnect the bat-
tery cables from the battery. Raise the front of the vehicle up on to the jack stands to obtain adequate access to
the bottom exhaust anges. Use large-base jack stands to support the vehicle. Do not rely on the jack! Block the
tires to prevent the vehicle from rolling off the jack stands.
2. Disconnect the spark plug wires by grasping and gently twisting the spark plug wire boots. Do not pull on the
wires! Brush or blow any debris, which may have collected around the manifolds or spark plugs. This will help
prevent foreign matter from entering the combustion chamber when the manifolds are removed. Spray WD-40
or some type of penetrating oil on all accessible fasteners and ttings before attempting to remove them.
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