20-180BK Complete Holley Mid-Mount Accessory Drive Kit
Instruction Manual
20-180BK Complete Holley Mid-Mount Accessory Drive Kit
Complete Holley Mid-Mount Accessory Drive Kit
Part Numbers: 20-180, 20-180BK, 20-180P, 20-185, 20-185BK, 20-185P, 20-190, 20-190BK, 20-190P, 20-200, 20-200BK, 20-200P, 20-205, and 20-205BK
Holley’s Mid-Mount complete accessory system has all accessories pulled in tighter than other accessory drives. Among the many swap-friendly features is the bracket-less assembly that actually mounts all accessories to the water pump directly.
Features:
- Bracket-less accessory mounting with ultra-easy assembly
- Bottom outlet heater hose options for swap application clearance
- LT1 style hairpin premium alternator
- LT1 style water pump design
- Compact SD7 A/C compressor
- Type II power steering pump with baffled reservoir
- OE pulley ratios for optimal accessory performance
- Available for LS and LT applications
- Billet tensioner cover (does not apply to 20-185)
- Billet alternator and compressor pulley covers (does not apply to 20-185, 20-185BK, and 20-185P)
- SFI certified damper w/hard and billet crank pulley (does not apply to 20-185, 20-185BK, and 20-185P)
Parts List:
PICTURE | QTY | DESCRIPTION | REPLACEMENT MANUFACTURER & P/N |
 | 1 | Manifold Assembly, Water Pump | Holley 97-163 (LS natural) / 97-167 (LS black) / 97-165 (LS polished) 97-164 (LT natural) / 97-168 (LT black) / 97-166 (LT polished) |
 | 1 | Gaskets, Water Pump | GM 12630223 (LS) / 12657430 (LT) |
 | 1 | Water Pump Drive Assembly / Gasket | Holley 97-200 / GM 12619770 |
 | 1 | Belt, 6 Rib Serpentine | BANDO 6PK1715 |
 | 1 | Thermostat 180° / housing | Holley 97-169 (set) GM 89018168 (thermostat only) |
 | 1 | NPT Adapters (2) & Plugs (3) | Holley 97-177 |
 | 1 | Tensioner Assembly with Smooth Pulley | Holley 97-179 OR, Gates 38163 |
 | 1 | Alternator/harness pigtail | Holley 197-302 (natural) / 197-303 (black) / 197-304 (polished), Pigtail Holley 197-400 |
 | 1 | SD7 A/C Compressor | Holley P/N 199-102 (natural) / 199- 104 (black) / 199-106 (polished) |
 | 1 | Adapter Manifold for A/C Compressor | Holley 199-202 |
 | 1 | P/S Pump with Reservoir | Holley P/N 198-101 |
 | 1 | P/S Pressure Hardline to -6 AN, Banjo Bolt, crush washers (2), & Hardware | Holley 198-203 |
 | 1 | P/S Pulley | Holley P/N 97-152 |
 | 1 | Damper Crank Bolt (OE) | GM 12557840 (LS1, 2, 3, 6, & LT) /11570163(LS7) |
| HARDWARE…………………………….. (REPLACEMENT KIT 97-162) | HARDWARE APPLICATION | ||
 | 1 | Oversized Washer, M8 | Tensioner |
 | 1 | Button Head Bolt, M8 x 1.25 x 70 | Tensioner |
| 1 | Button Head Bolt, M10 x 1.5 x 80 | Alternator (outside) | |
| 2 | Button Head Cap Bolt, M6 x 1.0 x 18 | Thermostat Housing | |
| 6 | Button Head Bolt, M6 x 1.0 x 20 | Water Pump to Manifold | |
 | 2 | Socket Head Cap Bolt, M8 x 1.25 x 95 | A/C Compressor |
| 1 | Socket Head Cap Bolt, M10 x 1.5 x 75 | Alternator (inside) | |
 | 5 | Flange Head Bolt, M8 x 1.25 x 115 | Manifold to Engine Block |
| 1 | Flange Head Bolt, M8 x 1.25 x 50 | Manifold to Engine Block | |
| 3 | Flange Head Bolt, M8 x 1.25 x 30 | Power Steering Pump | |
| Included Only With: 20-180, 20-180BK, 20-180P, 20-190, 20-190BK, 20-190P, 20-200, 20-200BK, and 20-200P | |||
 | 1 | Crank Pulley | Holley 97-159 (LS1, 2, 3, & 6) / 97- 160 (LS7) / 97-161 (LT) |
 | 1 | Hub, Inner Shell, Damper assembly, Outer Shell, & Hardware (crank pulley bolts included with this hardware). | Holley 97-190 (LS1, 2, 3, & 6) / 97- 191 (LS7) / 97-192 (LT) |
| Included Only With: 20-185, 20-185BK, 20-185P, 20-205, and 20-205BK | |||
 | 1 | One-piece damper/pulley | Holley 97-205 (LS1, 2, 3, & 6) / 97- 325 (LT) |
| Included Only With: 20-180, 20-180BK, 20-180P, 20-185P, 20-190, 20-190BK, 20-190P, 20-200, 20-200BK, and 20-200P | |||
 | 1 | Alternator Pulley Cover & O-ring | Holley 97-187 (black) /97-188 (polished) |
| Included Only With: 20-180, 20-180BK, 20-180P, 20-190, 20-190BK, 20-190P, 20-200, 20-200BK, and20-200P | |||
 | 1 | A/C Compressor Pulley Cover & Hardware | Holley 97-185 (black) / 97-186 (polished) |
| Included Only With: 20-180, 20-180BK, 20-180P, 20-185BK, 20-185P, 20-190, 20-190BK, 20-190P,20-200, 20-200BK, and 20-200P | |||
 | 1 | Tensioner Cover & Hardware | Holley 97-158 (black) / 97-157 (polished) |
| Included Only With: 20-200, 20-200BK, and 20-200P | |||
 | 1 | Throttle Body Angle Adapter & Hardware | Holley 717-15 |
IMPORTANT NOTE IF PAINTING COMPONENTS: The alternator and A/C compressor are ground through the water pump manifold. If painting or coating the manifold, the mating surfaces must all be bare metal allowing a ground path from the accessories’ mounting feet to the engine block and ultimately the negative terminal on the battery.
Technical Support: 1-866-464-6553
Assembly Instructions
HELPFUL HINT: The below assembly order is optimized for explanation and the average application. It may be easier to preassemble some components to the manifold before mounting to the engine.
Torquing of the components may however be easier after mounting. The only component that cannot be preassembled is the tensioner, as it would prevent access to a mounting bolt. Keep in mind adding components increases the overall size and weight and may require an additional person when mounting.
Steam Vent Inlet Port (optional):
A port is provided for convenient and simple routing of LS steam venting. If not utilizing the steam inlet port, install the 1/8” NPT plug provided. Use thread sealant (Loctite® brand 567 pipe thread sealant or equivalent). Install to finger tight, and then tighten 2 to 3 rounds.
Suggested accessories (not included): Holley 26-552 complete LS steam tube plumbing kit
ECU Water Temperature Sensor Installation (LT applications only): 
Install the original temperature sensor removed from the LT water pump manifold. Torque to 15 ft./lb.
Water Pump and Gasket Installation:
Helpful Hint: Do not confuse these M6 x 20 long bolts with the two M6 x 18 bolts to be used later.
NOTE: Torque M6 button head bolts to 85 in/lbs. Use a standard 4mm hex tool. Do not use a ball hex tool. Do not over tighten.
Damper / Crank Pulley Assembly Installation (whichever applies to your kit):
SFI-certified damper and billet pulley
One-piece OE style damper/pulley
- Remove the original bolt (retain this bolt for later use)
- Remove the existing damper/pulley with an LS-style puller like ICT P/N 551329.
- Apply to lubricate to the bore of the new damper hub and to the hub side of the original bolt head
- Use an installation tool like ICT 551141 to install the new damper/pulley. Remove tool.
- Install the original bolt and torque to 240 ft./lbs. to seat and then remove the bolt.
During torqueing, use a flywheel holder like Trick Flow TFS-90326 to prevent the engine from turning. - Install and tighten the new (unused) bolt to 59 ft./lbs.
- At this time, reference the front of the engine with the handle of the wrench. Mark with tape where 125° of clockwise rotation would be from where 59 ft./lbs. was obtained.
- Rotate the wrench/bolt 125°. Remove the flywheel holder tool. The installation process is now complete
NOTE: Only use a new (unused) bolt for the last steps.
Manifold Installation:
Thermostat and Heater Hose Adapter Installation:
WARNING: Do not plug all heater passages. For safe LS/LT engine start-up cooling this path must stay open. If not utilizing a heater core, install a jumper hose between the two barbs. 
Configurations: On some swap applications there is not clearance for side heater hose outlets. There are optional bottom outlets for these applications.
Assembly: Install the smaller 5/8” barb on either the rear side or rear bottom port first, then the large 3/4” barb on either front port. Plug the unused ports.
Use thread sealant (Loctite® brand 567 pipe thread sealant or equivalent). Install to finger tight, then tighten 2 to 3 rounds.
Alternate Installation Option (additional parts required): 
For applications with interference on the passenger side, the shown swivel adapters are available (not included).
PICTURE | DESCRIPTION | MANUFACTURER & P/N |
 | Swivel Thermostat Housing | Mr. Gasket 2670 (chrome) 2670BK (black) 2670NA (natural) |
 | Early Style Thermostat (required for above) | Mr. Gasket 6368 |
 | Swivel 90° 3/4” Barb 3/4” NPT | Earl’s SS988412ERL |
| Swivel 90° 5/8” Barb to 3/4” NPT | Earl’s SS988409ERL |
Alternator Installation
NOTE: Torque M10 bolts to 36 ft./lbs.
ALTERNATOR WIRING: See instructions included with the alternator for wiring directions.
P/S Pump -6 AN Adapter Assembly
NOTE: After assembly torque M8 bolts to 18 ft./lbs. and banjo bolt to 25 ft./lbs.
P/S Pump Pulley Installation
HELPFUL HINT: Pulley installation tools are available for rent at most auto parts stores.
P/S Assembly Installation:
NOTE: Torque M8 bolts to 18 ft./lbs.
IF THERE IS RESERVOIR INTERFERENCE: In a few applications, the supplied reservoir may interfere with the vehicle. In these cases, use Holley P/N PS0001ERL to adapt the supplied P/S pump’s inlet to a connection appropriate for use with most remote reservoirs. Reservoir options include Holley P/N 198-211 and 198-212 when used with adapter AT785010ERL.
HYDRO-BOOST BRAKE APPLICATIONS: These applications often require an additional reservoir inlet. Use PS0001ERL and AT785010ERL adapters with either 198-211 or 198-212 Holley reservoirs for these applications.
A/C Compressor Installation:
NOTE: After assembly torque M8 bolts to 18 ft./lbs. 
Remove the compressor’s cover plate making sure none of the mineral oil spills out. Make certain the two 0-rings stay inside the compressor grooves.
Install the supplied line adapter manifold and M8 X 18 socket head bolts.
NOTE: Torque M8 bolts to 18 ft./lbs.
Tensioner Installation:
NOTE: Torque M8 bolt to 18 ft./lbs.
Belt Installation:
After routing the belt use a 1/2” square drive wrench to pull the tensioner all the way down and work the belt on from the rear.
Accessory and Tensioner Covers:
(Cosmetic covers are included with some kits. If not included, these can be purchased individually.
See instructions included with cover for installation procedures)
Throttle Body Angle Correcting Adapter (LT applications only):
The angle adapter is required when using an LT car-style intake to prevent interference from the downward-facing throttle body. See included instructions for installation procedures.
199R11335
Revision Date: 11-15-21
