INSTALLATION INSTRUCTIONS
®
FORM 1455 (REV. C) 3/00
AND TECHNICAL INFORMATION
RETURN LOG
PART NO. 4302
FIGURE 1
DUAL FEED HOLLEY CARB
(VACUUM SECONDARY, DOUBLE PUMPER,
OR DOMINATOR)
SEALING GASKET – 2 PLACES
(NOT SUPPLIED)
FUEL LINE FROM FUEL PUMP
UP TO 550 HP: AN-8 OR 1/2" HARDLINE
UP TO 800 HP: AN-10 OR 5/8" HARDLINE
UP TO 1200 HP: AN-12 OR 3/4" HARDLINE
RETURN LINE SIZE
UP TO 180 GPH PUMP: AN-8 OR 1/2" HARDLINE
UP TO 360 GPH PUMP: AN-10 OR 5/8" HARDLINE
UP TO 720 GPH PUMP: AN-12 OR 3/4" HARDLINE
HOLLEY TO AN-8 COUPLER – 2 PLACES
AN-8 TO 3/8" NPT ADAPTER – 2 PLACES
O-RING – 2 PLACES
FUEL LINE
FROM FUEL PUMP
IN
FUEL LOG EXTENSION
REGULATOR ASSEMBLY
RETURN LINE
BACK TO FUEL TANK
1/8 NPT GAUGE PORT – 2 PLACES
(PLUGS SUPPLIED)
O-RINGS
PRESSURE ADJUSTMENT SCREW
JAM NUT
AN-10 FITTING – 2 PLACES
1. Mallorys fuel return log features a built-in adjustable return
regulator. The pressure can be adjusted while the engine is
running. There are no shims to change and the fittings do
not need to be loosened to adjust the pressure. The pres-
sure is adjusted by loosening the jam nut and turning the
adjustment screw.
2. Fuel pressure is adjustable between about 3 PSI and 12
PSI. Exact range depends on the size of the fuel pump and
return line size.
3. All fittings are included. The center-to-center distance of the
outlets is adjustable to allow use on most Holley carbs.
4. Thread sealant may be necessary on the 3/8" NPT fittings
and on the 1/8" NPT gauge ports.
5. Repair kits are available and include all necessary O-rings.
These kits can be used for repair, or to convert from gaso-
line to alcohol or from alcohol to gasoline.
Use Kit #3173 for gasoline applications.
Use Kit #3174 for alcohol applications.
Lubricate O-rings prior to assembly.
6. If AN-8 (or 1/2" hardline) fuel lines are used, the AN-10 fitting(s)
can be replaced with AN-8 fittings (such as Earls PN 985081).
7. Assembly is shown with the inlet at the rear of the carb. As-
sembly can be flipped over so that the inlet is near the front.
IMPORTANT NOTE
This fuel log is assembled with o-rings for use with gaso-
line. O-rings are also included for use with alcohol fuel. If
you use alcohol fuel, disassemble the Mallory Return Log
and replace the installed o-rings with those supplied.
--OVER--
MALLORY [ MALLORY PERFORMANCE CLUB ]
