Vortech Engineering GM 7.4 User manual

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
1988-1995 Model Years
50 State Smog Legal per CARB EO #D-213-17
GM 7.4 Light Truck
Supercharger System
Installation Instructions
®
ENGINEERING, LLC
1650 PACIFIC AVENUE • CHANNEL ISLANDS, CA 93033-9901 • [phone]
FAX [phone] • www.vortechsuperchargers.com • M-F 8:00 AM - 4:30 PM PST

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
Proper installation of this supercharger kit requires general automotive mechanic
knowledgeandexperience.Pleasebrowsethrougheachstepofthisinstructionmanual
prior tobeginningtheinstallationtodetermineifyoushouldreferthejobtoaprofessional
installer/technician. Please call Vortech Engineering for installers in your area.
FOREWORD
© 2001 VORTECH ENGINEERING, LLC
All rights reserved. No part of this publication may be reproduced, transmitted, transcribed,
or translated into another language in any form, by any means without written permission
of Vortech Engineering, LLC
ii

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
Table Of Contents
FOREWORD ...................................................................................................................... ii
TABLE OF CONTENTS ..................................................................................................... iii
NOTICE.............................................................................................................................. iv
TOOL & SUPPLY REQUIREMENTS.................................................................................. v
PARTS LIST - 1988-1993 7.4 TRUCK ............................................................................... vi
PARTS LIST - 1994-1995 7.4 TRUCK ............................................................................... ix
1. COMPONENT REMOVAL ...................................................................................... 1
2. CRANKSHAFT PULLEY INSTALLATION .............................................................. 1
3. OIL DRAIN LINE..................................................................................................... 2
4. OIL FEED LINE ...................................................................................................... 3
5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM ... 3
6A. MAIN BRACKET AND POWER STEERING PUMP - 1988-1993 MODELS .......... 7
6B. MAIN BRACKET AND POWER STEERING PUMP - 1994-1995 MODELS .......... 8
7. COOLING FAN SPACER ....................................................................................... 9
8. SUPERCHARGER MOUNTING............................................................................. 10
9. FACTORY ACCESSORY DRIVE BELT AND SUPERCHARGER DRIVE BELT .... 10
10. DISCHARGE PLENUM .......................................................................................... 11
11. AIR FILTER, INLET DUCT AND PLENUM ............................................................. 12
12. FINAL REASSEMBLY & CHECK ........................................................................... 13
iii

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
This product is protected by state common law, copyright and/or patent. All
legal rights therein are reserved. The design, layout, dimensions, geometry,
and engineering features shown in this product are the exclusive property of
Vortech Engineering, Inc. This product may not be copied or duplicated in
wholeorpart,abstractlyorfundamentally,intentionallyorfortuitously,norshall
any design, dimension, or other information be incorporated into any product
or apparatus without prior written consent of Vortech Engineering, LLC.
NOTICE
iv

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
Congratulations on selecting the best performing and best backed automotive
supercharger available today... the VORTECH® V-2® Supercharger!
Before beginning this installation, please read through this entire instruction booklet and the Street
Supercharger System Owner's Manual which includes the Limited Warranty Program and the Warranty
Registration form and return envelope.
Vortech supercharger systems are performance improving devices. In most cases, increases in torque of 30 to
35% and horsepower of 35 to 45% can be expected with the boost levels specified by Vortech Engineering. This
product is intended for use on healthy, well maintained engines. Installation on a worn-out or damaged engine is
not recommended and may result in failure of the engine as well as the supercharger. Vortech Engineering is
not responsible for engine damage.
Installation on new vehicles will not harm or adversely affect the break-in period so long as factory break-in
procedures are followed.
For best performance and continued durability, please take note of the following key points:
1. Use only premium grade fuel 92 octane or higher (R+M/2).
2. The engine must have stock compression ratio.
3. If the engine has been modified in any way, check with Vortech prior to using this product.
4. Alwayslistenforanysignofdetonation(pinging)anddiscontinueharduse(noboost)untilproblemisresolved.
5. Perform an oil and filter change upon completion of this installation and prior to test driving your vehicle.
Thereafter,alwaysuseahighgradeSFratedengineoilorahighqualitysynthetic,andchangetheoilandfilter
every3,000milesorless.Neverattempttoextendtheoilchangeintervalbeyond3,000miles,regardless
of oil manufacturer's claims as potential damage to the supercharger may result.
6. Beforebeginninginstallation,replaceallsparkplugsthatareolderthan1yearor10,000mileswithoriginalheat
range plugs as specified by the manufacturer and reset timing to factory specifications (follow the procedures
indicatedwithin thefactory repairmanualand/orasindicatedonthefactoryunderhood emissionstag). Donot
useplatinumsparkplugsunlesstheyareoriginalequipment.Changesparkplugsevery15,000milesandspark
plug wires at least every 50,000 miles.
1988 - 1995
GM 7.4 LIGHT TRUCK
Installation Instructions
50 State Smog Legal, as per CARB EO #D-213-17
v
TOOL & SUPPLY REQUIREMENTS
•Factory Repair Manual
•Timing Light
•3/8" socket and drive set: SAE and Metric
•Drill motor, 3/32" and .046" drill bits
•1/2" breaker bar and 4" extension
•Large screwdriver or pry bar
•3/8" NPT tap and handle or socket
•Flat #2 screwdriver
•Phillips #2 screwdriver
•Center punch and 3/4" drift punch
•Open end wrenches: 3/8", 7/16", 1/2, 9/16", 5/8", 3/4", 7/8", 10, 13 & 15mm
a "Slimline" 19mm - Snap-On part # LTAM1719
•Power Steering Pulley Puller & Installer (1994 models only)
Snap-On Puller #CJ117B2
Snap-On Installer #CJ113B
If your vehicle has in excess of 10,000 miles since its last spark plug change, then you will need:
•Spark plug socket
•NEW spark plugs
•Hammer
•Adjustable wrench
•Oil Filter Wrench
•Oil Filter
•SF Rated Quality
(or synthetic) Engine oil
•Heavy grease Silicone
sealer

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC)) vi

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
1988-1993 7.4 Truck
Part No. 4GC218-090SQ
PARTS LIST
Part Number Description Quantity
4GC112-010 AIR INTAKE ASSEMBLY 1
4GB012-010 Air Filter Cover 1
4GC012-012 Air Inlet Tube 1
4FA012-012 90°Intake Elbow 1
7P375-017 3/8” NPT x 1/2” Straight Hose Barb 1
7S350-200 3-1/2” x 2” Sleeve 1
7R002-056 #56 Hose Clamps 2
7R002-052 #52 Hose Clamps 4
7E010-046 #8 x 3/4” Sheet Metal Screws 2
7U035-000 3-1/2” x 10” Flex Hose 1
8H040-040 Air Filter 1
7U030-005 1/2” x 5” Oil Drain Hose 1
7U035-000 3-1/2” x 12” Flex Hose 1
7R001-008 #8 Stainless Hose Clamps 2
4GC112-020 AIR DISCHARGE ASSEMBLY 1
4GB040-060 Air/plenum Gasket 1
4GC012-020 Steel Discharge Tube 1
4GC050-011 Intake Plenum 1
7A312-050 5/16-18 x 1/2” Bolts 2
7J312-000 5/16” SAE Flat Washers 2
7P125-025 1/8” NPT to 5/32” Barb 1
7R002-044 #44 Hose Clamps 4
7S275-200 2-3/4” x 2” Sleeves 2
7P750-102 3/4" NPT x 1" 90°Hose Fitting 1
7P750-100 3/4" NPT x 1" Straight Hose Fitting 1
7R002-016 #16 Hose Clamps 4
8D001-001 Bypass Valve 1
7U030-046 5/32" x 24" Vacuum Line 1
7P156-082 5/32" Tee 1
7U034-016 1" x 3" Heater Hose 1
7U034-016 1" x 8.5" Heater hose 1
8H040-075 1" Filter 1
4FA111-032 BELT TENSIONER ASSEMBLY 1
7J012-092 12mm Flat Washers 3
4FA011-032 Belt Tensioner Plate 1
7C012-050 12mm x 1.75 x 50mm Bolt 1
4FA016-150 Smooth Pulley Tensioner 1
2A017-010 Idler Pulley Spacer 1
7C012-020 12mm x 1.75 x 20mm Bolts 2
7C012-022 12mm x 1.75 x 22mm Thin Head Bolt 1
7G010-175 12mm x 1.75 Nut 1
4GC160-010 FUEL CONTROL ASSEMBLY 1
4GC152-011 Spacer Block Assembly 1
4GB112-022 Plenum Rod Assembly 1
4GB101-002 FUEL PUMP ASSEMBLY 1
8F001-002 155 Inline Fuel Pump 1
7R003-024 1-1/2” Adel Clamp 1
5W001-011 16-14 GA Eyelet 1
5W001-001 Wire Tap 1
5W001-010 16-14 GA insulated Female Slides 6
5W001-014 Fuse Holder 1
5W001-015 Blade type 20A Fuse 1
5W001-017 Large Ring Terminal 1
8F101-200 T-Rex®Wiring Assembly 1
5W001-002 Fuse Tap 1
7R001-008 #8 Hose Clamps 2
7P625-001 Fuel Adapter Fitting 1
7U030-050 12mm x 8” PCV Hose 1
7J010-001 #10 Flat Washers 4
7F010-032 10-32 Nylock Nut 2
7U100-055 6” Nylon Tie Wraps 4
7C011-075 10/32” x 3/4” Cap Screw 1
Part Number Description Quantity
2E228-090 V-2SQ SUPERCHARGER ASSEMBLY 1
4GC111-021 MOUNTING BRACKET ASSEMBLY 1
4GC010-034 Mounting Plate 1
4GC010-043 Attachment Plate 1
4GC010-054 Stiffener plate 1
4GC011-021 Mounting Bracket 1
4GC017-011 .125 Mounting Plate Spacer 1
7A375-550 3/8-16 x 5-1/2” Bolt 1
7F375-016 3/8-16 Nuts 3
7K375-040 3/8” AN960 Flat Washers 5
7J375-044 3/8” SAE Washers 8
7A375-100 3/8-16 x 1” Bolts 10
7C010-025 M10-1.5 x 25mm Bolts 2
7A312-100 5/16-18 x 1” Bolts 4
7J312-000 5/16” SAE Flat Washers 8
4GC010-010 Mounting Bracket Support 1
7A375-208 3/8-16 x 2” Bolt 1
7A375-276 3/8-16 x 2-3/4” Bolt 1
7F312-018 5/16-18 Nuts 4
4GB017-011 1” Throttle Spacer 1
7A375-124 3/8-16 x 1-1/4” Bolts 2
4GC116-010 CRANK PULLEY ASSEMBLY 1
4GB016-011 Crank Pulley 1
4GC017-041 Crank Pulley Spacer 1
7B375-400 3/8-24 x 4” Bolts 3
7J375-044 3/8” SAE Washers 3
7L375-075 3/8" Lock Washers 3
4GC017-010 Spacer Fan 1
7C080-055 M8 1.25 x 55 Studs 4
2A046-598 Belt 1
7B500-400 1/2-20 x 4” Bolt 1
4GC130-026 OIL FEED LINE ASSEMBLY 1
7U030-026 1/4” x 16" Oil Feed hose 1
7P525-067 .500 Crimp Ferrules 2
7P250-066 #4 Swivel x 1/4” Hose Barb Fittings 2
7P250-036 #4 Flare to 1/4” NPT 1
7P125-026 1/8” NPT 90°Fitting 1
7P250-034 1/4” NPT x 1/4” NPT Straight Tee 1
7U100-055 6” Nylon Tie Wraps 3
4GC130-036 OIL DRAIN ASSEMBLY 1
7R001-008 #8 Stainless Hose Clamps 2
7U030-036 1/2” x 36” Oil Drain Hose 1
7P375-033 3/8” NPT x 3/8” NPT Street Elbow 1
7P375-017 3/8” NPT x 1/2” Straight Hose Barb 1
7U100-055 6” Nylon Tie Wraps 4
5A001-004 FUEL INJECTION COMPUTER 1
®
ENGINEERING, LLC
IMPORTANT: Before beginning installation, verify that all parts are included in the kit.Report any shortages
or damaged parts immediately.
vii

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC)) viii

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
Part Number Description Quantity
2E228-090 V-2 SQ SUPERCHARGER ASSEMBLY 1
4GG111-021 MOUNTING BRACKET ASSEMBLY 1
7A437-600 7/16-14 x 6” Bolt 1
7J438-081 7/16” SAE Washer 1
7A375-300 3/8-16 x 3” Bolt 1
7F375-016 3/8-16 Nut 2
7K375-040 3/8” AN960 Flat Washers 7
4GG017-021 1.895 Spacer A 1
4GG017-031 1.083 Spacer B 1
4GG010-034 Mounting Plate 1
4GG011-021 Mounting Bracket 1
4GG010-044 Attachment Plate 1
4GG017-041 .220 Spacer C 1
7J375-044 3/8” SAE Washers 3
7A375-100 3/8-16 x 1” bolts 5
4GC010-010 Mounting Bracket Support 1
7A375-208 3/8-16 x 2” Bolt 1
7A375-276 3/8-16 x 2-3/4” Bolt 1
4GB017-011 1” Throttle Spacer 1
4GG017-043 1/2" Spacer 2
7K312-001 8mm Washers 2
7C080-025 8mm x 1.25 x 25mm 2
4GC112-010 AIR INTAKE ASSEMBLY 1
4GB012-010 Air Filter Cover 1
4GC012-012 Air Inlet Tube 1
4FA012-012 90°Intake elbow 1
7P375-017 3/8” NPT x 1/2” straight hose barb 1
7S350-200 3-1/2” x 2” Sleeve 1
7R002-056 #56 Hose Clamps 2
7R002-052 #52 Hose Clamps 4
7E010-046 #8 x 3/4” Sheet Metal Screws 2
7U035-000 3-1/2” x 10” Flex Hose 1
8H040-040 Air Filter 1
7U030-005 1/2” x 5” Oil Drain Hose 1
7U035-000 3-1/2” x 12” Flex Hose 1
7R001-008 #8 Stainless Hose Clamps 2
4GC130-026 OIL FEED LINE ASSEMBLY 1
7U030-026 1/4” x 16" Oil Feed Hose 1
7P500-067 .500 Crimp Ferrules 2
7P250-066 #4 Swivel x 1/4” Hose Barb Fittings 2
7P250-036 #4 Flare to 1/4” NPT 1
7P125-026 90°1/8” NPT x #4 Fitting 1
7P250-034 1/4” NPT x 1/4”NPT Straight Tee 1
7U100-055 6” Nylon Tie Wraps 3
4GC130-036 OIL DRAIN ASSEMBLY 1
7R001-008 #8 Stainless Hose Clamps 2
7U030-036 1/2” x 36” Oil Drain Hose 1
7P375-033 3/8” NPT x 3/8” NPT Street Elbow 1
7P375-017 3/8” NPT x 1/2” Straight Hose Barb 1
7U100-055 6” Nylon Tie Wraps 4
1994-1995 7.4 Truck
Part No. 4GG218-090SQ
PARTS LIST
Part Number Description Quantity
5A001-004 FUEL INJECTION COMPUTER 1
4FA111-032 BELT TENSIONER ASSEMBLY 1
7J012-092 12mm Flat Washers 3
4FA011-032 Belt Tensioner Plate 1
7C012-050 12mm x 1.75 x 50mm Bolt 1
4FA016-150 Smooth Pulley Tensioner 1
2A017-010 Idler Pulley Spacer 1
7C012-020 12mm x 1.75 x 20mm Bolts 2
7C012-022 12mm x 1.75 x 22mm Thin Head Bolts 1
7G010-175 12mm x 1.75 Nut 1
4GC160-010 FUEL CONTROL ASSEMBLY 1
4GC152-011 Spacer Block Assembly 1
4GB112-022 Plenum Rod Assembly 1
4GB101-002 FUEL PUMP ASSEMBLY 1
8F001-002 155 Inline Fuel Pump 1
7R003-024 1-1/2” Adel Clamp 1
5W001-011 16-14 GA eyelet 1
5W001-001 Wire Tap 1
5W001-010 16-14 GA Insulated Female Slides 6
5W001-014 Fuse Holder 1
5W001-015 Blade type 20A Fuse 1
5W001-017 Large Ring Terminal 1
8F101-200 T-Rex®Wiring Assembly 1
5W001-002 Fuse Tap 1
7R001-008 #8 hose Clamps 2
7P625-001 Fuel Adapter Fitting 1
7U030-050 12mm x 8” PCV Hose 1
7J010-001 #10 Flat Washers 4
7F010-032 10-32 Nylock Nut 2
7U100-055 6” Nylon Tie Wraps 4
7C011-075 10/32” x 3/4” Cap Screw 1
5W001-024 Mini Fuse Tap 2
4GG116-010 CRANK PULLEY ASSEMBLY 1
4GB016-011 Crank Pulley 1
7B375-400 3/8-24 x 4” Bolts 3
7J375-044 3/8” SAE Washers 3
7L375-075 3/8” Lock Washers 3
4GC017-010 Spacer Fan 1
2A046-598 Belt 1
4GG017-042 Crank Pulley Spacer 1
7C080-055 M8 1.25 x 55 Studs 4
7B500-400 1/2-20 x 4” Bolt 1
4GG112-020 AIR DISCHARGE ASSEMBLY 1
4GC012-020 Steel Discharge Tube 1
4GB050-010 Intake Plenum 1
7R002-044 #44 Hose Clamps 4
7S275-200 2-3/4” x 2” Sleeves 2
4GB040-060 Air/Plenum Gasket 1
7J312-000 5/16" SAE Flat Washers 2
7A312-100 5/16-18 x 1” Bolts 2
7P125-105 1/8” NPT to 5/32” Barb 1
4CB017-011 1/2” Spacers 2
7P750-102 3/4" NPT x 1" 90°Hose Fitting 1
7P750-100 3/4" NPT x 1" Straight Hose Fitting 1
7R002-016 #16 Hose Clamps 4
8D001-001 Bypass Valve 1
7U030-046 5/32" x 24" Vacuum Line 1
7P156-082 5/32" Tee 1
7U034-016 1" x 3" Heater Hose 1
7U034-016 1" x 8.5" Heater hose 1
8H040-075 1" Filter 1
ix
IMPORTANT: Before beginning installation, verify that all parts are included in the kit.Report any shortages
or damaged parts immediately.
®
ENGINEERING, LLC

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC)) x

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
1. COMPONENT REMOVAL
A. Disconnect the battery (negative lead).
B. Remove and set aside the following compo-
nents:
•The top portion of the fan shroud
•The accessory drive belt
•The cooling fan assembly
•The crankshaft pulley
•The air filter canister assembly and hose
•The intake air resonator (detach from inner
fender)
•The power steering pump pulley (1994
models only)
2. CRANKSHAFT PULLEY INSTALLATION
A. Removethecrankshaftpulleyfromtheengineif
not already done.
B. Place the Vortech provided crank pulley and
spacer inside the stock pulley. (See
Fig. 2-a .)
C. Line up bolt holes and, if necessary, press
pieces together or pull them together by gradu-
ally tightening the bolts.
D. Reinstall the pulleys as a unit onto the crank-
shaftbalancerassemblyusingthree3/8-24x4"
bolts and supplied 1/2-20 x 4" center bolt. (See
Fig. 2-a .)
3 BOLTS: 3/8-24 X 4"
SPACER
NEW ADDITIONAL PULLEY
1
NOTE: If the vehicle is a 1993 model year or later,
it will be necessary to purchase the stock
airinlet resonator.TheChevrolet partnum-
ber is 25097949
Fig. 2-a

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
7/8" TO REAR
OF BOLT
OIL PAN
OIL FILTER
PUNCH HOLE THROUGH
DOWN 3"
3. OIL DRAIN LINE
A. Raise the front of the vehicle and support with
appropriate jack stands.
B. Toprovideanoil drainforthesupercharger,itis
necessarytomakeaholeintheoilpan.Itisbest
topunchtheholeratherthandrill.Removepaint
aroundtheholeareasothatitdoesnotflakeinto
the pan.
C. Make a mark on the oil pan on the driver’s side
ahead of the oil filter. The mark should be 3"
belowthe boltflange andrearward ofthe fourth
bolt 7/8". (See
Fig. 3-a .) You may choose a
differentplace,ifnecessary;however,takecare
not to damage any internal parts. The drain
hoseshouldgraduallydropwithnodipsorkinks
and should be above the oil level.
D. Use a small center punch to perforate the pan
and expand hole. Switch to a larger diameter
punch and expand the hole further to approxi-
mately9/16"diameter.Mostpunchesaremade
from hexagon material and may be placed in a
socketwithanextensiontomakethisprocedure
easier.
E. Tap the hole with a 3/8" NPT tap approximately
1/4" deep. Pack the flutes of the tap with heavy
greasetocatchandholdthechips.Oncethetap
is removed, it must be cleaned and repacked
beforetappingresumes.Useasmallmagnetto
check for any stray chips in the threads after
completing the tapping procedure.
F. Thoroughly clean the threaded area with ac-
etone or other solvent. Apply a small amount of
siliconesealertothenewthreads.Applyasmall
amountofsiliconesealertothethreadsofthe3/
8" NPT hose fitting and secure in hole. Make
sureasealisformedallaroundthefitting.Allow
sealer to cure completely.
G. Routethelineforwardalongthetoprailoftheoil
pan and secure to the oil cooler line with the tie
wrapsprovided. Temporarilycover end ofhose
andsecureoutoftheway.Thereturnisagravity
drainand should beroutedto provide agradual
drop.
H. Drain and replace engine oil and change filter.
NOTE: This method of rolling over the lip of
the hole and tapping works well if
CAREFULLY doneandshould cause
no problems.
Fig. 3-a
2

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
4. OIL FEED LINE
A. Thesuperchargerusesengineoilforlubrication
and must have an oil feed line connected to a
filteredoilaccessontheengineandanoilreturn
ordrain.(See
Fig.4-a .)Connectiontotheoilpan
must be above the oil level.
B. Disconnect the wire connector and remove the
oil pressure sending unit. The sender is found
on the left side at the front of the engine block.
Install the TEE provided in the port with the
branch pointing forward. Place the pressure
sender in front branch of the TEE, secure and
reconnect the wire. Place the flare fitting in the
remaining port and secure.
C. Connect the hose to the flare fitting and secure
with tie wraps. Take care that the feed line will
not rub on the sheet metal inner fender.
D. Temporarily cover the end of the hose and
protect it from dirt until connecting to the super-
charger.
OIL PAN
ENGINE BLOCK
A. Remove the TBI unit from the manifold. (See
Fig. 5-a .) Remove old gaskets and clean the
gasket surfaces.
B. To prevent pressurized fuel and air leakage
around the throttle shaft, it is necessary to
normalize the pressure. To accomplish this,
modify the throttle body by drilling two small
holesfromthebasesurfacetothethrottleshafts.
You may “layout” the location by following the
templateonpage6ortransferitdirectlyfromthe
gasketprovided.Useasmallcenterdrilltostart,
then a #56 or 3/64" diameter drill bit and drill
throughthebaseofthethrottlebody until the bit
firmly contacts the shafts.
C. Assemble the throttle body, the new injector
spacerblockandgaskets.Placethegasketwith
the small vent holes on top of the spacer. Place
the gasket without holes on the bottom. On
some models dowel pins have been provided
for alignment. Use the two special threaded
rods, nuts and one longer bolt to secure the
throttle body and the Vortech spacer to the
manifold.
WARNING: The oil system contains a small
orificethatis easilyplugged.DO
NOT use any type sealant on
any feed line threads. Instead,
use clean engine oil. Disas-
semble and blow out entire line
if you have any doubts.
5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM
3
Fig. 5-a
Fig. 4-a

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
D. Mounttheadditional fuel pump totheinnerside
of the frame rail beneath the driver's side floor.
Usetheshorterhoseprovidedtohelplocatethe
pump the correct distance from the filter. This
hose has an adapter fitting on the filter end.
Securethepumptotheframeandhosewiththe
clamp and fastener provided. (See
Fig. 5-a .)
E. Mark and drill a 3/16" hole in the frame near the
fuel pump to mount relay and wiring harness.
Mount relay with supplied #10 hardware.
F. Fromrelayterminal#85,taptheyellowwireinto
thesolid graywire inthe harnessrunning along
the driver's side frame member. Use the sup-
plied scotchlock.
G. Connect the short red wire from relay terminal
#87 to the (+) terminal on the fuel pump.
H. Connectthelongerblackwirefromthe(-)termi-
nal at the fuel pump to a clean ground.
I. Connecttheshortblackwirefromrelayterminal
#86toacleanground(relayscrewmountworks
well).
J. Connect the long red wire from relay terminal
#30 to a (+) battery lug located in the engine
compartment.
K. Plumbthe pump tothesupplementary injectors
as per the schematic on page 5. Much of this
assembly has been done by Vortech.
L. Plumb the new pressure regulator and outlet,
routing the regulator to the throttle body inlet
using the adapter fitting and O-ring.
M. Route the Vortech SFIC wiring harness and
vacuum line through the firewall. Mount the
SFIC unit inside the vehicle beneath the steer-
ing column using the Velcro®strips provided.
N. Connect the wires for the Vortech SFIC. Attach
theblack wire toground. Connect thered to the
"4WD"fuselocationinthe stockfuseblock(this
location is also found on 2WD trucks) with the
special adapter provided (on 1995 models, the
fuse box containing the "4WD" fuse is located
inside the vehicle on the left hand side of the
dashboard). Connect the brown wire to the
negative side of the ignition coil tach pickup
(loose male connection located on coil har-
ness).
5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM - Cont'd.
NOTE: Make sure all small holes are aligned and
not plugged with gasket sealer when in-
stalled.
4

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM - Cont'd.
Fig. 5-a
5
NOTE: Factory fuel return line must be
attached to original fitting on TBI unit.
THROTTLE SPACER BLOCK
PLACE 3/8" ADAPTER FITTING
INTO TBI FUEL INLET
USE 3/8" ADAPTER FITTING
AT STOCK FUEL FILTER
CONNECT TO FITTING ON
DISCHARGE PLENUM
VORTECH FUEL PUMP
(-) GROUND
SUPPLEMENTAL
INJECTORS
VORTECH
SUPPLEMENTARY FUEL
INJECTION COMPUTER
BROWN WIRE IGN COIL (-) NEG.
BLACK WIRE GROUND
VORTECH
FUEL PRESSURE
REGULATOR
RELAY
TERMINAL #87
25A
4WD FUSE BOX
FUSE BOX
INJECTOR CONNECTORS ARE
INTERCHANGEABLE AND
REVERSIBLE
UPPER
FITTING
LOWER
FITTING
SOLID GRAY WIRE IN FUEL
PUMP HARNESS (RUNNING
ALONG THE DRIVER'S SIDE
FRAME MEMBER
(+) FUEL PUMP
(+) BATTERY LUG
RELAY WIRING
SCHEMATIC
87a
87
30
8586
GROUND
3/8” HOSE
3/8” BARB
1/4 NPT
FEMALE
5/16”
BARB x
1/4 NPT
FEMALE
5/16”
HOSE

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
4.550
.100
.100
TEMPLATE
THROTTLE BODY
DRILL TWO HOLES THROUGH BOTTOM OF THROTTLE BODY
UNTIL POSITIVE THROTTLE SHAFT CONTACT
USE 3/64" OR #56 (.046) DIAMETER
Fig. 6A-a
5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM - Cont'd.
6

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
A. Install the connector bracket to the front of the
stock bracket at the power steering pump with
thetwolongermetricfastenersprovided.Some
vehicles use metric and others use standard
SAE threads. Check the threads on the fasten-
ers you have just removed against the ones
supplied prior to installation. Both metric and
standardfastenershavebeenprovidedforyour
convenience.Leavethefastenersslightlyloose
until all fasteners are started.
B. Position the main supercharger mounting plate
andinstallthefastenersasshowninthegraphic.
Makesurenottoforgetthe1/8"longtubespacer
behind the plate on the inward bolt.
C. Removethefastenersecuringthestockbracket
to the cylinder head on the outward side. Install
thecastaluminummountingbracketbehindthe
newmountingplate and ontopofthe tab onthe
stock bracket (where you just removed the
fastener).Placethe3/8-16x5-1/2"boltthrough
theplateandintothehead,passingthroughthe
tab on the stock bracket.
D. Remove the smaller alternator fastener and
installtheupperstiffenerplateasshown.Donot
secure the stiffener until the supercharger is
installed.
E. Attach the stiffener rod between the cylinder
head and mounting plate. A one inch spacer is
usedatthecylinderheadasshowninFig.6A-a.
F. Secure all other bracket fasteners at this time.
FOR 1988-1993 MODELS
STIFFENER PLATE
ATTACHMENT PLATE
3/8-16 x 2"
3/8-16 x 2-3/4"
1" SPACER
.125 SPACER
ALTERNATOR
STOCK BOLT
3/8-16 x 5-1/2"
3/8-16 x 1"
SUPPORT
MOUNTING BRACKET
POWER STEERING PULLEY 5/16-18 x 1"
3/8-16 x 1" OR
M10-1" x 25
3/8-16 x 1"
5/16-18 x 1"
MOUNTING PLATE
6A. MAIN BRACKET AND POWER STEERING PUMP - 1988-1993 MODELS
Fig. 6A-a
7

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
A. Disconnect all electrical connections at the al-
ternator.
B. Remove the alternator from the vehicle and set
aside.
C. Loosen the main cast iron accessory mounting
bracket.
D. Remove the power steering pump fasteners
andsetpumpasidetemporarily.Removemount-
ing bracket.
E. Locate the power steering pump into the sup-
pliedmountingbracket.Installthetworightside
bolts finger tight.
F. Fasten the new mounting bracket to the engine
leaving the bolts loose.
G. AttachtheVortechmountingplatebysandwich-
ingthelowerleftmountingplateholeinbetween
themountingbracketandpowersteeringpump.
Use spacer 'C' (0.22") in between the plate and
the power steering pump mounting boss. Use
the original bolt to secure the assembly.
H. Slide spacer 'B' (1.083) in between the mount-
ing bracket and the back of the supercharger
plateasshownin
Fig6B-a .Threadthesupplied
7/16-14 x 5-3/4" bolt into the bracket. Do not
tighten.
I. Reinstallthealternatorandallelectricalconnec-
tions.
J. Installthe attachmentplate onto theback ofthe
alternator mount using the original bolt. Place
spacer 'A' (1.895) in between the attachment
plate and the back of the supercharger mount-
ing plate using a 3/8-16 x 3" bolt, 3/8" nut and
washers.
K. Connect the support rod between the cylinder
headandtherearofthemountingplate.Usethe
3/8-16 x 2-1/4" stainless steel bolt and a 3/8-16
x1-1/2"bolt,nutandwashersforattachment.A
1"spacerisusedatthecylinderhead as shown
in
Fig 6B-a . Tighten all bracket fasteners at this
time.
L. Reinstall the power steering pump pulley.
M. 1995 models use a new style ABS control unit
that must be adjusted slightly to provide super-
charger clearance. Remove the front two of the
four 8mm bolts fastening the ABS mounting
plate to the vehicle. Pry the front of the ABS
mounting plate up approximately 1/2" to 5/8".
Installthesupplied1/2"spacersunderneaththe
mounting plate and secure with the supplied
8mm bolts and washers.
6B. MAIN BRACKET AND POWER STEERING PUMP 1994 - 1995 MODELS ONLY
8

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
6B. MAIN BRACKET AND POWER STEERING PUMP 1994 - 1995 MODELS ONLY, Cont'd.
7. COOLING FAN SPACER
A. Thread the four M8-1-1/4" X 55 threaded studs
intotheholesonthewaterpumptotheshoulder.
Loctite®thread locking compound is recom-
mended on threads.
B. Place the 5/8" fan spacer over the studs and
onto the pilot.
C. Placethe cooling fanassembly onto thespacer
andsecurewiththenutsandwashersprovided.
D. Reinstall the fan shroud upper half.
FOR 1994-1995 MODELS ONLY
SPACER
C, .22"
SPACER 'A' 1.895
ALTERNATOR
ATTACHMENT PLATE FACTORY
ALTERNATOR
BOLT
1" SPACER
3/8-16 X 2-1/4"
STAINLESS
STEEL BOLT
SUPPORT ROD
3/8-16 X 1" BOLT,
AN 3/8" WASHERS
3/8-16 X 1-1/2"
FACTORY
POWER
STEERING
PUMP BOLT
7/16-14 X 5-3/4"
POWER STEERING PUMP
MOUNTING FLANGE
SPACER 'B' 1.083
3/8-16 X 3"
9
Fig. 6B-a
3/8-16 x 2-3/4"
STAINLESS
STEEL BOLT
3/8-16 x 2"

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1 (88-95 GM Lt Trk(4GC))
ALT
TENSIONER
SUPERCHARGER
POWER
STEERING
WATER
PUMP
CRANKSHAFT
IDLER
A/C TENSIONER
ALTERNATOR
3/8-16x1-1/4"
3/8-16x1"
SUPERCHARGER
MOUNTING BOLTS
MOUNTING PLATE
A. Using the stock accessory drive belt, install as
originally installed.
B. Loosely attach the tensioner bracket to the
superchargerwith the fastenersprovided.(See
Figs.9-a,9-b .)Makesuretousethewasherson
all locations.
C. Adjustbelttension byrotatingtheadjusterplate
with a 1/2" drive socket and extension and
secure.
MOUNT TENSIONER
WITH SUPPLIED FASTENERS
YOU MUST USE THE WASHERS
MOUNT TENSIONER WITH
SUPPLIED FASTENERS.
NOTE: WASHERS MUST
BE USED ON ALL LOCA-
TIONS.
NOTE: It will be necessary to reset the
belt tension after approximately
250 miles.
FOR 1988-1993 MODELS ONLY
8. SUPERCHARGER MOUNTING
A. Attachthesuperchargerdrainhosetothefitting
on the bottom of the supercharger and secure
withtheclampprovided.Makesuretorotatethe
clampso itdoes notinterfere withthe mounting
plate.
B. Mount the supercharger to the mounting plate
with the four 3/8 16 x 1" bolts and washers and
one3/8-16x1-1/4"boltandwasherfortheplate
stiffener (See
Fig. 8-a .) (For 1994-95 models,
the supercharger is mounted with five 3/8-16 x
1" bolts and washers only. The stiffener is not
used.)
C. Attach the oil feed line and secure.
WARNING: The oilsystemcontainsasmall
orifice that is easily plugged.
DO NOT use any type sealant
onanyofthethreads. Instead,
use clean engine oil. Disas-
sembleand blowoutentire line
if you have any doubts.
Fig. 8-a
9. FACTORY ACCESSORY DRIVE BELT AND SUPERCHARGER DRIVE BELT
Fig. 9-a
Fig. 9-b
10