How To Install Holley's Mid-Mount Accessory Drive Kit Onto An LS Engine


How To Install Holley's Mid-Mount Accessory Drive Kit Onto An LS Engine


By now it’s a bit of a cliché that LS swaps go into everything. After all, “LS swap the world” is a phrase almost every car guy and girl has heard (and chances are good that you’ve said it).

But there’s a really good reason why the LS engine is so popular when it comes to swapping power into just about everything. The engine design is powerful, compact, enjoys a ton of aftermarket support, readily available, and dependable. Good stuff all around.

But that doesn’t mean some things still can’t be improved. For example, depending on whether the engine originally came out of a truck, a Corvette, or an F-body, there were differences in the water pump, intake manifold, oil pan and other things. Sometimes, figuring out what you have and what combination you need to make it fit in your project can make a sane person scream.

LS Mid-Mount Accessory Drive Install measurements

Before the kit was even ordered, we downloaded and printed out dimensional drawings off of Holley’s website that allowed me to check against a mockup engine in the Corvette and quickly determine whether the Accessory Drive Kit would work. Holley also has low- and high-mount kits depending on your needs.

Thankfully, the aftermarket has stepped in to make smart accessory systems that allow easy LSX swaps into practically anything. That’s the situation that appeared when trying to drop a 6.0L LQ9 (the iron-block truck version of the LS) into a 1980 Chevrolet Corvette. The Corvette is nothing special itself and LS swaps into these cars have been done before, but the problem was the way the engine sits in the chassis. Any front drive accessories that sat low in front of the engine would hit the upper control arms.

With the C3, there are two problems to contend with: you couldn’t have anything too low, and with the low hoodline, any alternators or A/C pumps sticking out of the hood wouldn’t work, either. Holley’s LS Mid-Mount Accessory Drive Kit (p/n 20-186) is able to pack in an alternator, power steering pump and an A/C Compressor into one incredibly tight package. Not only does it clear the chassis and suspension, because everything is spun by a single serpentine belt, it also creates enough space to allow for a pair of electric fans behind the radiator. Follow along as we take a look at the design and install it onto the LQ9.

LS Mid-Mount Accessory Kit water pump

Everything in the kit is thoroughly modern. In fact, the water pump is a Gen V LT1 style design, which is nice because the efficiency will help keep high-horsepower engine builds appropriately cool. Here, it's about to be bolted into the custom water pump casting. A quality metal gasket is also included.

LS Mid-Mount Accessory Kit harmonic damper install

But before the water pump can go on, we need to install the included harmonic damper. The Holley kit will install just as easily on an existing engine already in the car, but since this is a new build, that dictated the order of some of the steps. For example, in order to get good front seal life, it is critical that the front cover be centered around the crank snout. The easiest way to do this is to leave the bolts on the cover loose, then install the damper. There are no dowel pins on an LS and since the bolts are still loose, the cover will shift a bit and allow the seal to center around the damper hub, Then you can finish tightening the bolts on the front cover. If you are a hard-core racer, some kits can also be had with an SFI-certified balancer.

Holley LS Mid-Mount Accessory Kit water pump casting installation

Here’s a better look at the water pump casting getting torqued up to the block. This casting is key to the system. Because every component connects to the water pump housing, it not only makes for a more compact setup, it also eliminates all brackets and adjusters. And if you’ve ever struggled to make components of a front drive all work together because the block has been decked or the bolt holes on a set of aftermarket heads aren’t in the right place, then you can appreciate everything mounting off of a purpose-made casting. Simplicity for simplicity’s sake can be a great thing.

LS Mid-Mount Accessory Kit Alternator

Holley’s 150-amp premium alternator is built for performance applications. For example, it is designed to be able to handle 30% higher rpm’s than a conventional alternator so it won’t fly apart when you are pegging the rev limiter on the drag strip or at the autocross. Also, all the fasteners needed are also included in the kit, so there’s no digging through the random bolts bucket looking for the right length.

LS Mid-Mount Accessory Drive Air Conditioning

The AC compressor mounts up on the upper passenger side. Right now, the inlet and outlet has been blocked off, but the kit includes the necessary fittings to get everything plumbed up.

LS Mid-Mount Accessory Kit Serpentine Belt

The serpentine belt routing is well designed so only a single tensioner is needed.

LS Mid-Mount Accessory Kit heater hose plumbing options

There are two sets of heater hose plumbing locations right beside the thermostat housing. In this image, we already have the hose fittings threaded into the upper two openings, but if you have a fitment issue with whatever chassis you are swapping an LS into, you also have the lower pair of options (which have plugs in this image) which may make it easier to route the hoses, depending on your needs.

LS Mid-Mount Accessory Kit Power Steering Pump Pulley Install

A properly sized pulley is provided with the power steering pump, but it must be pressed on. Thankfully, you can borrow a proper pulley install tool from just about any chain store. With the right tools, it's really a piece of cake.

LS Mid-Mount Accessory Kit power steering pump

The Holley power steering pump has an integrated reservoir to clean up plumbing inside the engine compartment. The aluminum pump is rated at 2.8 gallons per minute and 1,100 to 1,200 psi at 1,500 rpm.

LS Mid-Mount Accessory Kit Power Steering pressure hardline fitting

Here’s a nice touch. The standard pressure outlet on the front of the LS power steering pump is practically impossible to reach with the pulley in place and the alternator directly above it, so Holley includes a custom pressure hardline with a banjo fitting that connects into the pressure outlet and allows you to conveniently hook up your plumbing here behind the reservoir.

LS Mid-Mount Accessory Drive Kit belt alignment check

Misaligned pulleys lead to thrown belts, and thrown belts lead to cursing on the side of the road. Even though we were working with a comprehensive kit and not mix-and-match parts, it's still always a good idea to check pulley alignment with a straightedge. We were all good, so it’s time to install the belt.

LS Mid-Mount Accessory Kit Install serpentine install

Belt installation was as simple as following the routing in the instructions, pulling the tensioner out of the way with a 1/2-inch ratchet and dropping it in place.

LS Mid-Mount Accessory Kit Install Finished

Here's the completed product on our LQ4, which is just about ready to give our C3 Corvette the power it could have only dreamed of having when it rolled off of the line back in 1980.


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