Adding an Electric fuel pump is a safety concern for older cars and
trucks. If you want to add the fuel pump then a roll-over inertia
switch
should be added.
One like used in the late model Ford products can be used. It is easy
to install and will stop the fuel pump in the event of an accident. The
Car Quest
auto parts number for the switch is (6l5z9341a and the 3 wire connector
is
96-7552). I would consider such a switch a "MUST" when installing an
electric fuel pump.
The Ford switch has a manual reset, so they can be reset if activated
by a bump or some
other minor disturbance. When installing the switch make sure the
switch is level
and mounted in a vertical position. The car / truck should be level
also to have correct
operation. Mount the switch so you would have easy accesse if it
is tripped. Most Ford produts so equipped have the access port in the
trunk or passenger side pannel
just in front of the door interior where the switch control may be
accessed if a reset is
required. The switch has a normally open side so that wire can be used
to turn on a light on
the dash so the driver will know if the switch is tripped and needs to
be reset.

Make sure to mount the inertia switch in a vertical position on a solid part of the body of the car or truck. Put it in a place where it will be protected from water and other road material.

The image above and in the link below have been changed 6-20-07
The fuel tank unit in the middle left side of the above electrical
diagram is the fuel pump, and the inertia switch just to the right of
the fuel pump. The normally open contact of the inertia switch is not
used in the diagram. I included a hand written diagram of a simple
connection that can be used on an older truck or car. The normally open
contact (3) of the inertia switch can be used to turn on a small 12 / 6
volt light on the dash so the driver will know if the inertia switch
has opened and need to be reset before the car or truck will start. The
link below will open a page with a large electric diagram that is shown
above so you will be able to read it with out a magnifying glass, but
the load time for the large diagram is long so be ready for a wait
before printing.Make sure the inertia switch is in series with the fuel
pump and on the hot or 12/6 volt side as show in the above diagram. The
inertia switch has to open the hot lead going to the fuel bump to stop
it during an accident.