Edelbrock PRO-FLO XT 3527 User manual

1
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
TABLE OF CONTENTS
Part #3527 and #3528
Introduction.................................................................................................................................................1
Components................................................................................................................................................2
Preliminaries...............................................................................................................................................3
Fuel System................................................................................................................................................6
Induction System ......................................................................................................................................10
Sensors ....................................................................................................................................................13
O2 Sensor Installation ...............................................................................................................................15
Main System Harness ...............................................................................................................................16
Ignition System .........................................................................................................................................25
Other Applications.................................................................................................................................... 26
Software Installation .................................................................................................................................28
Calibration Selection .................................................................................................................................29
System Start-Up........................................................................................................................................30
Electronic Engine Management .................................................................................................................33
Pro-Flo Quick Tuning Guide.......................................................................................................................34
Calibration Module Flowchart....................................................................................................................36
Parts and Part Numbers ............................................................................................................................37
Service & Warranty ...................................................................................................................................39
INTRODUCTION
Thank you for selecting the Edelbrock Pro-Flo XT Fuel Injection System. This Multi-Point Fuel Injection System has been designed for 350 c.i.d.
small-block Chevrolet engines, and is designed to provide excellent performance, fuel economy, and maintenance-free operation. Installation of
the Edelbrock Pro-Flo XT Fuel Injection System involves modifications to the fuel system, ignition system, induction system, and possibly the
valve train. Although there are steps that must take place before others, the modifications do not necessarily have to be performed in a particular
order. Each modification is described in a separate section in this manual. Please study these instructions carefully before beginning installation
of any part of the Pro-Flo XT system.
If you have any questions, do not hesitate to call our
EFI Technical Hotline at [phone], 7am-5pm PST, Monday-Friday
E-mail: [email protected]

2
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
PRIMARY KIT COMPONENTS
❑Electronic Control Unit/System ECU ❑Fuel filter
❑Calibration Module ❑Fuel rail assembly
❑Distributor conversion kit ❑Fuel pressure regulator
❑Fuel injectors ❑High pressure fuel pump
❑ECU power relay/Fuel pump relay ❑Intake manifold
❑Manifold Absolute Pressure (MAP) Sensor ❑Four barrel air valve
❑Manifold Air Temperature (MAT) Sensor ❑Idle Air Control (IAC) solenoid, integrated with air valve
❑Coolant Temperature Sensor (CTS) ❑Main system harness
❑Throttle Position Sensor (TPS), integrated with air valve ❑Fuel pump harness
❑Oxygen (O2) sensor ❑Installation package
❑USB/Serial Converter ❑Ignition Harness
❑Software CD ❑MSD Blaster Coil
❑Mallory Distributor
Many Pro-Flo XT components, including the Manifold Absolute Pressure sensor, fuel pressure regulator, Coolant Temperature sensor, and the fuel
filter are standard OEM pieces. In the event that one of these parts needs to be replaced, you are likely to find a replacement at your local parts
supplier, in addition to your local Edelbrock dealer or directly from Edelbrock. For a list of part numbers, refer to the PART NUMBERS section at
the back of this manual.

3
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
TOOLS AND EQUIPMENT
Use the following checklist for items needed.
❑Box and open end wrenches
❑Socket set
❑Distributor wrench
❑Pliers (channel locks and hose clamp)
❑Screwdrivers (regular and Phillips)
❑Torque wrench
❑Hammer
❑Gasket scraper or putty knife
❑Timing light
❑Vacuum gauge
❑Rags
❑Water bucket
❑Drill and bits
❑Hole saw (1 1/4-inch or 1 3/4-inch)
❑Tubing wrenches
❑Tubing cutter
PRELIMINARY CHECKLIST
1. CAREFULLY STUDY AND UNDERSTAND ALL INSTRUCTIONS, BEFORE BEGINNING THIS INSTALLATION.
NOTE: This installation can be accomplished using common tools and procedures. However, you should have a basic
knowledge of automotive repair and modification and be familiar with and comfortable working on your vehicle. If you do
not feel comfortable working on your vehicle, it is recommended to have the installation completed by a professional
mechanic.
2. Examine the Pro-Flo XT system for possible shipping damage. If damaged, contact your dealer immediately.
3. The 3527 & 3528 kits are designed for use with a standard Small Block Chevy V8 firing order.
4. Check all threaded manifold holes.
5. Check all internal manifold passages with a light and wire, making sure they are clean and unobstructed.
6. Check automatic transmission shift points before removal of your stock manifold and adjust linkage after Edelbrock
manifold installation for same shift points (if needed).
NOTE::We recommend that you refer to this checklist again after installation to be sure that you have completed all steps.
HARDWARE AND PARTS RECOMMENDED
Use the following checklist for items needed.
❑Intake gasket; #3527 kits use Edelbrock gaskets #7201; #3528
kits use gaskets #7235
❑Pipe plugs, if needed
❑5/16-inch steel tubing (approximate equal length to fuel pickup
line in tank)
❑Edelbrock Gasgacinch #9300
❑Loctite 598 OEM High Temperature Silicone Gasket (O2Sensor
Compatible)
❑Radiator coolant
❑Wiring diagram for your vehicle
❑Teflon tape or liquid Teflon thread sealer
❑Manifold bolt kit; #3527use #8504; #3528 uses #8516
❑195° Thermostat
❑Resistor type spark plugs (Use correct heat range for your
particular application
❑Set of low-resistance spark plug wires with high EMI suppression
(DO NOT use solid core spark plug wires)
❑Dynojet wideband commander (Optional, not included)
❑DB9 Serial cable (Optional, not included)
❑Late model low profile water neck such as Trans-Dapt #9229 or
GM #12342034 (chrome)

4
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
MANIFOLD & CARBURETOR HEIGHT VS.
PRO-FLO XT HEIGHT
1. Lay a straightedge (such as a yardstick) across the top of the air
cleaner from front to back.
2. Measure from block and manifold end seal surfaces to
straightedge.
3. Record these measurements (height A and height B).
4. Add height A and height B and divide by two to get the average
height.
5. The Pro-Flo XT manifold is 9” tall at the center and 9.125” at the
throttle body flange.
6. Compare this to your original measurements. If the Pro-Flo XT unit
is taller, subtract this amount from the hood clearance figure to
determine new hood clearance.
CAUTION: You must maintain at least 1/2-inch clearance between the
hood and manifold because of engine torque. If you have insufficient
clearance, a hood scoop may solve the problem.
EMISSION CONTROLS
The Edelbrock Pro-Flo XT system will not accept stock emissions
control systems. Check local laws for requirements before installing
the Pro-Flo system. Not legal on pollution-controlled motor vehicles.
DETERMINING HOOD CLEARANCE
NOTE: Check hood clearance before removing stock manifold.
1. Use modeling clay or putty to make five small cones, two or three
inches high.
2. Position cones on air cleaner at front, rear, each side, and on
center stud.
3. Close hood to locked position and re-open.
4. The height of the cones indicate the amount of clearance
between the hood and the air cleaner. Record these
measurements.

5
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
FUEL REQUIREMENTS
Because the Pro-Flo XT system uses an Oxygen sensor, you must use unleaded fuel only. Leaded fuels will damage the O2sensor. If you do use
leaded fuel in your vehicle, do not install the O2sensor and do not operate the vehicle in the closed loop fuel mode.
AUTOMATIC TRANSMISSION CHECK
For best performance, economy, and emissions, the shift point must be checked before and after the manifold change.
NOTE: This check should be performed ONLY at a sanctioned drag strip or test track.
With the shifter in Drive, accelerate to wide open throttle from a standing start. Hold in this position, noting speedometer MPH when the
transmission makes the first 1-2 shift. After the Pro-Flo XT system has been installed, make the same test, again noting MPH of this first shift.
The transmissions in certain vehicles require precise adjustments. We recommend that you consult a reputable transmission shop for final
adjustments once the Pro-Flo system has been installed. Incorrect shift points can result in transmission damage.
ENGINE CLEANING
Edelbrock recommends that the Pro-Flo XT system be installed on a clean engine in order to prevent dirt from falling into the engine lifter valley
or intake ports.
1. Cover ignition. Use engine degreaser and a brush to thoroughly clean the manifold and the area between the manifold and valve covers.
2. Rinse with water and blow dry.
EXHAUST MANIFOLD HEAT RISER VALVE
If your vehicle is equipped with an exhaust manifold heat riser valve (typically located on the passenger side of the vehicle below the exhaust
manifold), remove the valve for proper operation. If applicable, any air injection tubes must be removed and holes in the exhaust manifold
plugged for proper operation.
HEADERS
For best performance, headers are recommended. For this application, header primary tube diameter should be 1-3/4 inch, approximately 31
inches long and terminating into a 3 inch collector. The remainder of the exhaust system should consist of dual exhaust and tail pipes, at least 2-
1/4 inches in diameter with low back pressure mufflers.
COOLING SYSTEM
The minimum requirements for the thermostat are 180° but the ideal thermostat is 195°. When the vehicle is at 175 or below, system will stay
in cold start mode and not perform properly.

6
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
FUEL SYSTEM
Because your Edelbrock Pro-Flo XT system controls fuel delivery very differently than a carburetor, some conversions to your fuel system are
necessary. Pro-Flo XT electronic fuel injection requires high and constant fuel volume and fuel pressure. For this reason, a good primary fuel
line is critical. The Pro-Flo XT system includes a 3/8-inch high pressure fuel line which must be used as the primary fuel line. The fuel that
bypasses the injectors must be returned to the fuel tank via a return fuel line. If your vehicle is already equipped with a fuel pump bypass line,
this line can be used as the return fuel line. If not, the original primary line may be used as the return line. If desired, a 15 foot length of 3/8” ID
Pro Classic hose is supplied for use as the return line.
Many late-model cars are equipped with an additional fuel line which runs to a charcoal canister mounted on the driver side of the vehicle. This
line MUST be re-installed after the fuel system conversion and MUST NOT be used as the return fuel line.
Tank Side
Engine Side
FUEL PUMP AND FILTER
The Pro-Flo XT system uses a single Edelbrock high-pressure electric fuel pump which is
capable of pumping 50 psi. The pump relay will shut down the pump if it does not receive an
engine-run signal from the ECU, as in the case of a stall. This safety precaution is necessary
when using a high-pressure fuel line. The provided fuel filter should be mounted between the
engine compartment and the fuel pump to allow fuel to be pushed through the filter rather
than drawn through. Electrical connectors should face the front of vehicle. Make sure the
fuel pump is mounted at or below the bottom of your fuel tank. If the pump is mounted above
this point, fuel pump failure will occur.
FUEL PRESSURE REGULATOR AND FUEL SUPPLY LINE
Fuel pressure is as important as fuel volume, particularly in fuel injection. The Pro-Flo XT fuel pressure regulator maintains a constant pressure at
the injectors with a spring loaded by-pass to the return fuel line. Manifold Absolute Pressure references the regulator diaphragm to maintain
constant pressure across all 8 injectors, regardless of fluctuating manifold pressure (vacuum) level. The fuel that is not injected is returned to the
fuel tank via the return fuel line.
RETURN FUEL LINE
Due to the high fuel pressure used by the Pro-Flo system, the supplied 3/8-inch Pro Classic high pressure fuel line MUST be used as the
primary fuel line, and a bypass fuel return line must be installed. There are three options for installing a bypass return line.
1. Use the 3/8” Pro Classic rubber fuel line provided with the system as the fuel return line.
2. Use the vehicle’s existing primary line as the fuel return line with modification to the pick up as described below.
3. Use the vehicle’s existing return line (if so equipped) as the fuel return line. This option applies only to vehicles previously equipped with fuel
injection. If the vehicle is not already equipped with a return line, some fuel tank modifications are required for routing the return line
through the sending unit plate back into the tank. The first two methods listed below require some welding and should be done by a
professional radiator or fuel system repair shop.
Return Side Supply Side

RUBBER RETURN LINE METHOD
Drill a 5/16-inch hole in the sending unit plate adjacent to where the main line enters the tank. This will be the hole for your return line. Insert a
short length of 5/16-inch hard line (available at most radiator shops) into the hole and weld it to the sending unit plate. The hard line should
extend through the hole 1 to 2 inches on each side of the plate. Connect a length (at least 4 inches) of 5/16-inch rubber return line hose to the
hard line that will extend into the tank. Connect the rubber line to the fuel pickup line using tie wraps.
7
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
BULKHEAD FITTING METHOD
Drill a 9/16-inch hole in the sending unit plate adjacent to where the main line enters the tank. This will be the hole for your return line. Insert a
#6 AN bulkhead fitting (available at most radiator shops) into the hole, the narrow end of the fitting on the inside of the plate. Apply a rubber
washer or RTV sealant and fasten the fitting to the plate with the nut. Connect a length (at least 4 inches) of flexible return line (rubber or
braided hose) to the fitting end. Connect the return line to the fuel pickup line using tie wraps.
NOTE: THIS METHOD REQUIRES NO WELDING OF THE FUEL SYSTEM.
NOTE: Whichever method you use to install the return fuel line, be
careful to keep the end of the line away from the fuel pickup, as
shown. Otherwise, aerated return fuel can be drawn into the pickup.

HARD RETURN LINE METHOD
Drill a 5/16-inch hole in the sending unit plate adjacent to where the main line, enters the tank. This will be the hole for your return line. Insert a
length of 5/16-inch hard line (available at most radiator shops) into the hole and weld it to the sending unit plate. The hard line should extend
through the hole 1 to 2 inches on the outside of the plate. On the inside of the plate, the hard line should follow the contours of the fuel pickup
line. Bend the end of the return line away from the sock on the end of the fuel pickup line. Solder or weld the return hard line to the fuel pickup
line.
8
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
BULKHEAD FITTING METHOD
HARD RETURN LINE METHOD

9
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
NOTE: ALL WELDING AND SOLDERING OF THE FUEL SYSTEM MUST BE PERFORMED BY A
PROFESSIONAL RADIATOR AND/OR FUEL SYSTEM REPAIR SHOP.
FUEL SYSTEM INSTALLATION
1. Drain the fuel tank.
2. Remove all fuel lines from the tank and from the carburetor.
3. Remove the fuel tank.
NOTE: While the fuel tank is removed from the car, it is recommended that it be professionally
cleaned in order to remove any rust or dirt that may have accumulated inside and which could
damage the injectors.
4. Remove the sending unit from the fuel tank. Refer to the RETURN FUEL LINE methods above for
installing the bypass fuel return line.
5. Install the provided 3/8-inch primary fuel line directly above the original line, which may
now serve as a return line. Use large radius bends. Avoid the exhaust pipe and any
sharp edges.
NOTE: The 3/8” Pro Classic high pressure fuel line supplied with the Pro-Flo system
must be used as the primary fuel line. See the following section for assembly
instructions.
6. If you do not use the original fuel as the return line, route the return line directly
alongside the provided 3/8-inch primary fuel line.
7. Mount the fuel pump between the tank and the fuel filter as low and as close to the
fuel tank as possible. The pump is directional. Electrical connectors should face the
front of vehicle. The fuel pump needs to be at or below the bottom of the fuel tank.
8. Mount the fuel filter between the fuel pump and the engine.
9. Re-install the modified sending unit plate to the clean fuel tank.
10. Reinstall the fuel tank.
11. Attach the primary line and return line to the sending unit plate on the tank.
12. Re-attach all other fuel lines at the tank (vapor purge lines, etc., if so equipped).
13. Secure the primary and return fuel lines with the provided tie-wraps, or with Adel clamps if
available.
14. Re-attach all fuel lines to the induction system once it has been installed.
15. Use the 10-foot wiring harness to connect the fuel pump to the Main System Harness. Route the
harness away from the exhaust pipe and any sharp edges. This harness may be cut to length.
Replacement terminals are provided with the Pro-Flo XT system. Cover the connection to the
positive terminal with the sleeve and tie wrap provided. Refer to the MAIN SYSTEM HARNESS section of this manual for details.
16. Before starting the engine, turn the ignition key to the ON position 4 or 5 times to prime the electric fuel pump, fuel lines, and fuel rails. You
should hear the pump run for approximately 2 seconds each time. Check the entire fuel system for leaks. Refer to the SYSTEM START-UP
section of this manual for details.

10
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
INDUCTION SYSTEM
The Edelbrock Pro-Flo XT system delivers fuel and air to the engine via the induction system consisting primarily of a manifold, 90mm air valve,
fuel rails, and fuel injectors. The induction system is fully assembled, tested, seal checked, and flowed at the factory and is as easy to install as a
manifold. DO NOT DISASSEMBLE any of these components during installation.
INTAKE MANIFOLD
The new Edelbrock Pro-Flo XT manifold has been designed specifically
for electronic fuel injection applications.
90mm THROTTLE BODY
The Pro-Flo XT system uses a throttle body with 90mm air valve. The
air valve can flow up to 1000 cfm at 1.5" of mercury when wide open.
FUEL INJECTORS
The Pro-Flo XT #3527 & #3528
systems use high impedance pintle-
type fuel injectors. The injectors
are capable of flowing 29 lbs./hr. at
50 psi. The injectors mount directly
onto the manifold, one at each port,
for fuel delivery that is precisely
controlled and instantaneously
injected.
FUEL RAILS
The extruded aluminum rail assembly routes the high pressure fuel to
the injectors. Aluminum rails have an advantage over soft rails both in
terms of style and safety.
ASSEMBLING PRO-CLASSIC HOSE
Step One: Cut hose to length,
as straight and square as
possible, with razor blade-type
hose cutter or shears.
Step Two: Unscrew socket
from hose end. Push hose into
socket, turning counter-
clockwise, until hose is seated
against step in socket. Make
sure rubber part of hose does not
protrude into socket threads.
Step Three: Apply Russell
assembly lube to threads on
nipple assembly and in socket.
Insert nipple into socket/hose
and start threads by hand
(clockwise).
Step Four: Hold socket/hose in
vise. Turn nipple with wrench
until there is less than 1/16"
between nipple hex and socket.
Repeat Steps 1-3 for other end of
hose. Then, flush hose assembly
with solvent or soapy water and
blow clean with compressed air or
let air dry.

11
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
PRE-INSTALLATION
Before installing the induction system, take the following steps to ensure successful installation and performance
1. Check all components thoroughly for damage.
2. Make sure all throttle linkages open entirely and close freely.
3. Make sure all fuel inlet and vacuum ports are free from packing material.
4. Check the installation kit for proper parts.
REMOVING THE STOCK CARBURETOR AND MANIFOLD
1. Disconnect battery.
2. For ease of installation, keep all parts in order.
CAUTION: Do not remove manifold if engine is hot.
3. Drain radiator coolant (radiator drain plug is typically located on lower right facing engine).
4. Remove gas cap to relieve pressure. Disconnect fuel line and plug. Replace gas cap.
5. Disconnect all linkage from carburetor such as throttle, throttle springs, transmission, cruise control and automatic choke.
6. Tag and remove coil wires and sensor wires.
7. Remove previously marked vacuum lines.
8. Remove radiator hose, thermostat housing and thermostat, if mounted on manifold.
9. Remove all brackets from the manifold.
10. Loosen or remove valve cover bolts for manifold removal and replacement. It may be necessary to replace valve cover gaskets, if broken, to
prevent oil leakage.
PORT SURFACE CLEANING
When cleaning old gaskets from head surfaces, lay rags in the lifter valley and stuff paper into
the ports, to prevent pieces of the old gasket from falling into ports and combustion chambers.
When clean, remove paper, making sure that all particles fall on the rags in the lifter valley.
Remove rags, and wipe surfaces clean with rags soaked in lacquer thinner in order to remove
oil or grease. NOTE: This procedure is necessary to ensure proper sealing.
INSTALLING FITTINGS, PIPE PLUGS, AND STUDS
Do not over-tighten or cross-thread fittings, pipe plugs, studs, or bolts in your aluminum manifold. Damage to threads or a cracked mounting
boss may result unless caution is used when installing accessories.
Use high quality pipe thread sealant on all threads. Install fittings from your stock manifold.
NOTE: Vortec blocks (1996 & later) do not have an internal coolant bypass to the water pump. The Vortec Pro-Flo XT kit includes a fitting, hose,
and threaded orifice at the front of the manifold to connect an external bypass to the water pump. Standard blocks (1995 & earlier) using Vortec
cylinder heads should plug this port. Do not use this port for a coolant temperature sensor since the reduced orifice size may prevent an
accurate reading.

12
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
GASKET SURFACE PREPARATION
CAUTION: Replace all gaskets as recommended. Do not use race-type non-embossed gaskets for street applications. Due to material
deterioration under street driving conditions, internal vacuum and oil leaks may occur. We recommend Edelbrock gasket #7201 for kit #3527
and #7235 for kit #3528. Do not use Fel-Pro Permatorque Blue gaskets, which are designed for use on stock cast iron intake manifolds only.
1. Check gaskets on head surface and manifold to make sure they are correct. Embossed side faces up
(NOTE: In some cases, there may be a
different right and left side gasket. Make sure both are placed correctly.).
2. Coat head surface and both sides of gaskets with Edelbrock Gasgacinch #9300.
3. Apply Loctite 598 OEM High Temperature Silicone Gasket around water passages on head surface.
4. Gaskets and surface will become tacky to the touch within a few minutes. Carefully place gaskets on head surface, aligning ports and bolt
holes.
5. Edelbrock recommends the use of Loctite 598 OEM High Temperature Silicone Gasket instead of end seal gaskets. Apply a 1/4-inch thick
bead of sealant across each end seal surface, overlapping the intake gasket at the four corners
(NOTE: Use the recommended silicon
sealer. Others may damage the O2 sensor. This method eliminates end seal slippage and deterioration. For ease of installation, we
recommend using Edelbrock Manifold Bolt and Washer Kit #8564.)
.
6. Apply Edelbrock Gasgacinch #9300 to port surface of the manifold and to the head surfaces to ensure a good seal.
7. Apply RTV gasket sealer around water passages on the manifold.
8. Surfaces will become tacky to the touch within a few minutes.
INDUCTION SYSTEM INSTALLATION
1. Carefully position manifold and air valve on engine, centering bolt holes with the bolt holes in the head.
2. Apply thread sealer or Teflon tape to bolt threads where exposed to water or oil.
3. Hand tighten all bolts.
4. Torque all manifold bolts to 25 ft/lbs. Torque in the sequence illustrated.
5. Re-connect throttle linkage and springs, transmission, cruise control, and fuel lines. Check all linkage for smooth throttle operation from idle
to Wide Open Throttle.
Note: Do not install with a throttle rod, use a cable actuated throttle. See Throttle Cable Installation section for further details.
6. Re-tighten the valve cover bolts.
6
5
1
4
11
12
8
7
2
3
9
10
5
3
1
7
6
2
4
8
Kit #3527 Kit #3528

13
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
SENSORS
The Edelbrock Pro-Flo XT system interprets overall engine operating conditions and fuel/spark requirements based on readings from sensors that
measure specific engine conditions.
The Pro-Flo system includes five sensors:
1) Manifold Absolute Pressure
2) Manifold Air Temperature
3) Coolant Temperature
4) Throttle Position
5) Exhaust Oxygen (O2)
MANIFOLD ABSOLUTE PRESSURE SENSOR
The Manifold Absolute Pressure sensor, mounted on the intake plenum, converts air
pressure (load) in the manifold, to an analog signal sent to the ECU. For more information
on Manifold Absolute Pressure, refer to the section on Speed Density Electronic Engine
Management.
MANIFOLD AIR TEMPERATURE SENSOR
The Manifold Air Temperature sensor, is a thermistor
device which measures air temperature. This sensor must
be installed in the air intake tract between the filter and
the throttle body. Drill the inlet tube with a 3/4” drill,
deburr any sharp edges, install MAT sensor grommet, then
slide sensor into grommet.
NOTE: The end user is responsible for sourcing and
attaching an appropriate air filter and inlet tube to the
throttle body. The inlet has an outside diameter of 4.25”.

14
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
OXYGEN (O2) SENSOR
An oxygen sensor, installed on the header collector pipe, measures exhaust gas oxygen content and is used by the ECU to manage fuel delivery
under closed loop control. Installing the sensor requires drilling a 1/2-inch hole in the passenger-side header collector. The sensor is held in
place with the provided fitting which must be professionally welded into place. The red-lean/green-rich light on the Calibration Module is also
controlled by the O2sensor. The O2sensor is connected to the Main System Harness by Connector J18. Refer to the engine harness diagram on
page 20 of this manual for further detail.
NOTE: The Pro Flo system is now capable of using either a narrow
band or wide band O2 sensor. The difference between a narrow band
and wide band O2 sensor is the range over which the sensor is
accurate. A narrow band sensor is basically a switch that only tells
the ECU if the air fuel ratio (AFR) is richer or leaner than 14.7 to 1. A
wide band sensor/controller typically has a linear voltage output that
is accurate over a range of 10 to 20:1 AFR. The included wideband
sensor calibration is for use with the Dynojet Wide Band Commander
Air Fuel Ratio Monitor. See http://www.widebandcommander.com for
more information. To select the wideband option, install the included
O2 select jumper as shown in the next section. To use the default
narrow band option, leave the jumper off. A dust cap is provided for
protection when the connector is not in use.
THROTTLE POSITION SENSOR
The Throttle Position Sensor, an integral
part of the Pro-Flo throttle body,
measures throttle angle.
COOLANT TEMPERATURE SENSOR
The Coolant Temperature Sensor is a thermistor device like the Manifold Air Temperature sensor.
Resistance varies as coolant temperature rises and lowers. The Coolant Temperature Sensor is
located at the front of the manifold on the driver’s side.

15
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
O2SENSOR INSTALLATION
The exhaust gas oxygen content is determined by the oxygen sensor. The sensor signals the ECU, which compensates when the air/fuel mixture
is either rich or lean.
NOTE: It is recommended that the O2sensor installation be performed by a professional muffler shop.
1. Double check header gaskets, replacing if necessary.
2. Drill a 1/2-inch to 9/16-inch hole in the passenger-side header collector reducer, as close to the header flange as possible. (1" to 3" away)
NOTE: Before drilling, make sure the O2sensor will be mounted horizontally and within reach of the harness connector. Check to ensure
adequate clearance for the sensor, taking into consideration engine movement.
3. Fit the provided fitting into the hole in the exhaust pipe and weld into place.
4. Once it has been welded into place, clean the threads in the center of the fitting. If your exhaust is coated tap bung threads to ensure a
good ground for the 0/2 sensor.
5. Thread the O2sensor into the fitting. A high-heat anti-seize compound is included and needs to be applied to the sensor threads.
NOTE: The O2sensor has 18mm x 1.25 spark plug threads.
6. Attach the O2sensor to the main system harness. Refer to the MAIN SYSTEM HARNESS section of this manual.
NOTE: UNLEADED FUEL MUST BE USED ONCE THE O2SENSOR HAS BEEN INSTALLED.
O2 SELECT
JUMPER
O2 SELECT
JUMPER CAP
SELECT
J3
O2 SENSOR
INSTALL FOR WIDEBAND (OPTIONAL)
INSTALL FOR NARROW BAND (INCLUDED IN KIT)

16
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
ENGINE HARNESS LAYOUT

17
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
MAIN SYSTEM HARNESS
This diagram illustrates the chassis side of the Pro-Flo XT Main System Harness.

18
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc

19
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc
MAIN SYSTEM HARNESS
This diagram illustrates the engine side of the Pro-Flo XT Main System Harness.

20
Pro-Flo EFI Installation Instructions
©2008 Edelbrock Corporation
Brochure No. 63-3527
Catalog #3527, #3528
Rev. 8/08 - AJ/mc