PART NO

1964-67 GM A-Body LS Swap Engine Mounting Brackets
71221008HKR & 71221009HKR
Installation Instructions
Thank you for choosing to use HOOKER™ engine swap mounting brackets as part of your LS swap project. These mounting brackets
are part of the most comprehensively engineered system of mounting components, headers and exhaust systems available for this
application. Please read these instructions thoroughly before attempting installation.
PRE-INSTALLATION CONSIDERATIONS:
Successful installation of an LS engine using these components is more highly ensured by installing new body bushings
prior to installation of these components.
Installation of an LS engine with these brackets requires the use of new stock OE 4th-gen F-body LS engine mounts (ex: GM 22179268
or Anchor 3064) or aftermarket polyurethane inserts (Prothane 7-512 or Energy Suspension 3-1151) and a stock rubber, or aftermarket
poly transmission mount (Prothane 7-1604 or Energy Suspension 3-1108).
In addition, a pair of metric motor mount through-bolts and a pair of locking flange nuts will need to be sourced for connecting the
Hooker engine brackets to the motor mounts. Specification requirements are 10.9 M12 x 1.75 x 140mm (Fastenal P/N 0122037 or
equivalent) for the bolts and M12 x 1.75 class 8 (Fastenal P/N 11508236 or equivalent) for the nuts.
COMPATIBILITY INFORMATION:
When used with the related Hooker™ 71222008HKR transmission crossmember, each or these engine swap mounting bracket sets will
provide the most geometrically optimized LS engine/transmission mounting solution available for this vehicle platform.
These engine swap mounting bracket kits are designed for use with a Holley® 302-2 oil pan and have been validated to be compatible
with the following engine accessory drive systems and vehicle components:
Accessory drive systems – Both engine bracket kits are compatible with the Holley or stock Corvette (excluding the A/C
compressor/bracket, which must be relocated) or Truck (must use smaller 5” diameter power steering pump pulley and stock Denso
A/C compressor without rear pressure sensor) FEAD systems.
Air Conditioning/heater – Both engine bracket kits are compatible for use with the stock vehicle A/C evaporator case (relocation of the
rear coil on the passenger side valve cover is required) and low-mounted A/C compressors. The 71221008HKR forward-bias engine
bracket kit provides more desirable clearance for the stock heater core inlet/outlet stubs and the heater hoses.
Steering boxes/linkage – Both engine bracket kits are compatible with the stock Saginaw power steering box or Delphi 600 series
power steering box. Pro Forged brand tie rod ends and center link and Moog brand tie rod ends have been validated to be compatible
for use with either of these engine bracket kits and the Holley 302-2 oil pan.
Exhaust headers/manifolds – Both engine bracket kits are compatible with Hooker Blackheart LS swap headers developed for this
application and Hooker LS cast iron manifolds. Compatibility with any other brand/type of headers or exhaust manifolds has not been
validated.
Additional LS engine swap/performance components, such as accessory drive brackets, EFI fuel control systems, fuel filters, fuel
pumps, plumbing hose/fittings, and valve covers can be found at www.holley.com.
BEFORE BEGINNING…
Check that the hardware package includes the following:
Qty.
4
2
Description
3/8 x 1” Bolts
3/8 Carriage Bolts
Qty.
8
6
Description
M10 x 1.5 x 25mm Bolts
3/8 Nuts
INSTALLATION:
1. Remove the factory engine stands from the K-member and clean the bracket mounting surfaces.
2. Loosely attach the Hooker engine mounting brackets to the K-member, as depicted in Figures 1, 2 and 3, using the supplied 3/8”
bolts/nuts. Install the carriage bolts into the rectangular slot position on each bracket. The driver’s side bracket is identifiable by the
triangular shaped notch located on its outer profile. The passenger’s side bracket has a semi-circle shaped notch located along its
outer profile.
Figure 1 – Attach engine mounting brackets using the stock holes in vehicle frame that are circled above.
Figure 2 – Install carriage bolts into top rear hole of each bracket when installing 71221009HKR rear biased brackets.
Figure 3 – Install carriage bolts into top front hole of each bracket when installing 71221008HKR forward biased brackets.
2
3. Install new 4th-gen F-body OE rubber or aftermarket polyurethane mounts onto the LS engine using the supplied (x8) M10 bolts.
4. Install the engine and transmission into the car and couple the engine to the Hooker engine brackets using the user-sourced metric
cap screws and flanged locking nuts. Use of the 71221008HKR forward-bias engine bracket kit usually requires the engine and
transmission to be installed separately due to the close clearance between the Holley 302-2 oil pan and the back of the engine
crossmember.
5. Raise the rear of the transmission as high as it will go and install the stock or Hooker 71222008HKR transmission crossmember as
detailed below for the particular Hooker engine bracket kit/transmission combination you are installing.
NOTE: Each set of Hooker A-body engine swap brackets provides the user with unique fitment/compatibility advantages that
determine the amount of effort required to install a particular transmission and/ or engine accessory drive system in the swap
vehicle. The amount of work to be expected when installing either set of engine brackets with a particular transmission is
listed below. You may need to install the transmission multiple times (depending on the transmission) to obtain proper
clearance with the floor, so be sure to use suitable lifting equipment to avoid injury.
71221008HKR Forward-Bias Engine Brackets:
4L60-4L70 Installations 
No floor cutting required, but slight impact clearancing (hammering) of the floor MAY be required around the location of the
upper left bolt boss at the bellhousing/transmission case interface and WILL be required around the area of the 2-4 servo piston
bore/cap on the right side of the transmission case.

Install using a Hooker 71222008HKR transmission crossmember, per the instructions included in its packaging.

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
TH350, TH400, and 2004R Installations 
No floor cutting or floor modifications are required to install these transmissions.

Install using a Hooker 71222008HKR transmission crossmember (TH400 or 2004R transmissions) per the instructions included
in its packaging or by using the stock vehicle transmission crossmember (TH350 transmissions) and sliding it 1” forward on the
frame rails. You will need to drill new mounting holes in the frame rails for the purpose of attachment.

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
T56/T56 Magnum Installations 
Moderate floor cutting/modification is required. Cut a long slit down the center top of the tunnel and remove all of the tunnel
sheet metal directly above the transmission extension housing. After slitting/cutting of the floor, install the transmission per the
instructions included with the Hooker crossmember and pry open the tunnel on either side of the slit until sufficient clearance
above the transmission is obtained. Close up the slit with a narrow patch panel and rebuild the tunnel surrounding the extension
housing once the transmission is solidly mounted to the crossmember.

Install using a Hooker 71222008HKR transmission crossmember, per the instructions included in its packaging.

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
4L80/4L85 Installations 
No floor cutting required, but slight heating (oxy/acetylene torch) and/or focused impact clearancing (hammering) of the floor will
be required around the output speed sensor and electrical plug on the left side of the transmission, the cooler fittings/lines on the
right side of the transmission, and the two rear band anchor lugs that protrude from the top right side of the case near the rear of
the transmission.

Install using the Hooker 71222008HKR transmission crossmember, per the instructions included in its packaging.

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
71221009HKR Rear-Bias Engine Brackets:
4L60-4L70 Installations 
Moderate floor cutting/modification is required. The areas of sheet metal that will need to be modified will be directly above the
upper bolts at the transmission bellhousing/case interface and the area adjacent to the 2-4 servo piston bore/cap on the right
side of the transmission case.
3

Install using a Hooker 71222008HKR transmission crossmember, per the instructions included in its packaging.

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
TH350, TH400, & 2004R Installations 
No floor cutting or floor modifications are required to install these transmissions.

Install using a Hooker 71222008HKR transmission crossmember (TH400 or 2004R transmissions) per the instructions included
in its packaging or by using the stock vehicle transmission crossmember (TH350 transmissions).

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
T56/T56 Magnum Installations 
Extensive floor cutting/modification is required. Cut a long slit centered on top of the tunnel that extends from the top of the
hump in the firewall all the way to the front edge of the center body brace that is located behind the transmission. Pull/push both
sides of the cut firewall/tunnel upward as far as possible by hand (the use of gloves is highly recommended). Install the
transmission per the instructions included with the Hooker crossmember. Reform/trim the sheet metal around the installed
transmission/shifter housing and close up the remaining opening with a suitable patch panel.

Install using a Hooker 71222008HKR transmission crossmember, per the instructions included in its packaging.

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
4L80/4L85 Installations –

Moderate floor cutting/modification is required. Cut and remove the choked-down area of the tunnel that resides between the
rear of the transmission and the front edge of the center body brace behind the transmission then install the transmission per the
instructions included with the Hooker 71222008HKR transmission crossmember. Close up the exposed opening over the
transmission extension housing with a suitable patch panel.

Installation requires the use of a stock OE rubber replacement or Prothane 7-1604 poly transmission mount.
6. With the engine and transmission in place on the engine brackets and transmission crossmember, sight across the bottom of the
engine K-member and use a pry bar to level the engine oil pan and transmission crossmember with the bottom of the engine Kmember. Once level, tighten all six bolts attaching the engine brackets to the engine K-member.
7. Your LS swap engine and transmission are now mounted and ready to be outfitted with headers and an exhaust system. Hooker
1964-67 A-body LS swap headers and exhaust systems are specifically designed for use with these engine mounting brackets.
LIMITATION OF LIABILITY – DISCLAIMER:
HOOKER™ makes no warranties of merchantability, of fitness for particular purpose, or that its products are approved for general use,
or that its products comply with laws, regulations, or ordinances in the state where they may be sold to the ultimate purchaser, the
consumer.
Unless expressly stated to the contrary in the catalog, instruction sheet; or price list, the entire risk as to the conformity of any company
product in any such state and as to repair should the product prove to be defective or non-conforming, is on the retail purchaser, the
buyer, the ultimate consumer, of such product and it is not upon the seller, distributor, or manufacturer.
In this connection, the retail purchaser, the buyer, the ultimate consumer assumes the burden of the entire cost of any and all
necessary service, alterations, or repair.
Technical Support: 1-866-464-6553
© 2016 Hooker Headers, Inc. All rights reserved
199R11048
Date: 6-21-16
4