Vortech 1964-1967 Pontiac GTO Carbureted User Manual
Page 12
4
4. FUEL SYSTEM INSTALLATION
A.
Remove the fuel lines from the fuel pump
and remove pump from vehicle.
B.
Drill and tap the vent hole located in the
side of the fuel pump. If the hole is tapped
to 1/16”NPT, a 3/16” hose barb fitting (P/N:
7P062-187) may be installed.
C.
Plug any additional fuel pump vent holes.
D.
Re-install the fuel pump.
E.
Run a boost pressure line from the
carburetor enclosure to the top of the fuel
pump diaphragm. The end of the bulkhead
fitting that is inside the enclosure should be
left open.
NOTE:A stock fuel pump may be
satisfactory for mild engines.
The following steps will allow
the mechanical pump to
increase fuel pressure in
proportion to boost pressure.
(I.E.: stock fuel pressure =
5psi @ 0psi boost/
supercharged fuel pressure =
12psi @ 7psi boost.) If fuel
pressure is not maintained at
least 4 psi above boost
pressure, replace the stock
fuel pump with a higher flow
unit. Alternatively, a system
utilizing an electric fuel pump
may be used as long as the
regulator is boost referenced.