Let's face it, there's nothing worse than dropping that freshly-built engine under the hood for the first time, only to find that the alternator contacts one inner fender, the power steering pump whacks the crossmember, and the A/C compressor hits the other inner fender. Those big buck bracket kits can often times locate the accessories way out in the breeze, causing all kinds of fitment problems. It was these clearance issues that have frustrated builders for years that were in mind when Holley designed their new small block Chevy Mid-Mount Complete Accessory System.
Designed around a bespoke aluminum water pump manifold assembly, the Holley Mid-Mount Kit features a "bracket-less" design, with the accessories attaching directly to the water pump housing itself. This results in a more compact system, pulling the accessories in tighter than traditional designs, increasing the clearance often needed in tight engine compartments. A myriad of features, including many adapted from the C7 Corvette’s LT1 drive system, allows the Holley Mid-Mount Kit to not only solve the issues that crop up when shoe horning a larger engine in a tight engine compartment, it also incorporates modern technology in a simple design that cleans up any engine bay.
Here's our 377ci engine, fully dressed in Holley parts, ready for the installation of their Small Block Chevy Mid-Mount Complete Accessory System (20-240BK).
Holley's unique water pump manifold assembly incorporates all the mounting points for the alternator, power steering pump, and a/c compressor, without the need of any additional brackets and is the key to the kit's design. A C7 Corvette bolt-in water pump is just one of the many innovations incorporated within the kit.
While the front of the water pump manifold is completely unique, the backside is familiar small block Chevy fare, but with a twist. Holley's water pump housing is machined to use O-ring seals as opposed to the traditional gaskets.
All the hardware required to install the water pump, manifold assembly, and all the accessories are included in the kit.
A total of six fasteners are used to fasten the water pump manifold assembly to the block.
Four upper bolts attach to the traditional water pump mounting points, with two additional fasteners at the bottom of the manifold.
The water pump manifold comes machined with a number of outlets that offer the end user options when it comes to heater hose outlets or water temp sending unit locations, etc.
The six mounting fasteners get torqued to 30 ft/lbs.
With the water pump manifold in place, the LT1 cartridge-style water pump can be installed using the provided M6 button head bolts.
A compact A/C compressor and Type II power steering pump are standard fare, but the Holley alternator is pretty special. Designed in-house by Holley engineers, this premium alternator utilizes 6-phase technology, again found on C7 Corvettes, and features 150 AMP output, packaged in a compact, fully sculpted, all aluminum housing.
Installation of the accessories begins with the alternator, using the provided M10 x 80 button head bolts, fastened to 36 ft-lbs.
Before installing the power steering pump, the AN-6 line adapter needs to be installed, with a sealing crush washer on either side, and torqued to 25 ft/lbs.
Next, the power steering pulley is installed on the Type II pump using a pulley installation tool. When the pump shaft and pulley hub are perfectly flush, installation is complete.
The power steering pump attaches to the water pump manifold using a trio of M8 x 30 flange head fasteners, torqued to 18 ft-lbs.
The water pump manifold features unique machining that allows the A/C compressor to slide into place, without the fasteners fouling on the cylinder head or valve cover. One M8 x 95 flange head bolt is started on the inner set of A/C compressor ears and slid into place on the water pump manifold.
The second M8 x 95 fastener is then partially installed through the outer, rear compressor mounting ear and the compressor then rotated into place on the water pump manifold. After assembly, each M8 fastener is then torqued to 18 ft-lbs.
The shipping plate on the A/C compressor is then replaced with this machined aluminum piece using the provided O-rings and M8 x 18 socket head bolts.
The belt tensioner is then installed next, using an M8 x 70 button head bolt and washer.
The crank pulley is installed last, using three 3/8-24 x 1 1/4-inch flange head bolts to attach the pulley to the damper. A new crank bolt and washer is also included in the Holley kit. The damper bolts are torqued to 25 ft-lbs while the crank bolt gets 60 ft-lbs.
By rotating the belt tensioner using a 1/2-inch square drive breaker bar, the six-rib serpentine belt can now be routed and installed.
The last portion of the installation has to do with dressing up the front of the accessories, beginning with the A/C compressor clutch cover. Three 1/4-20 x 3/4-inch flat head fasteners are used to secure the clutch cover, torqued to 6 ft-lbs.
Installation of the alternator cover is even more simple. It consists of an O-ring installed inside the groove of the alternator pulley.
The cover is then simply pressed into service and held fast by the O-ring.
The tensioner cover is the last piece of the puzzle to our installation and features a retaining plate, cover, and a pair of M3 x 0.5 x 20 button head fasteners.
The retaining plate is first rotated into position behind the tensioner body.
The cover is then attached using the provided hardware. About 9 in-lbs is all that's required to hold the cover in place.
That's a wrap! As you can see, the accessories are tucked in nice and tight against the heads and sit lower that the valve covers. The all black finish should look great for many thousands of miles and will be easy to simply wipe clean when things get a bit grubby.
