How To Install Holley's Mid-Mount Accessory Drive Kit For GM Gen-V LT Engines


How To Install Holley's Mid-Mount Accessory Drive Kit For GM Gen-V LT Engines


Holley Performance has pretty much taken over the entire LS swap market. You can get dang near everything you need to swap one of GM’s potent LS engines into your vehicle from Holley’s legion of brands. The newest engine from GM, the 5th generation small-block LT-series, is no different. While it did take a few minutes for the LT to catch on in the swap world, it is quickly taking hold. There are some inherent difficulties with the Gen V engines when it comes to swapping these direct-injected engines, namely the complete lack of power steering from the factory.

The 2019-up 6.6L L8T has a power steering pump, but none of the others do. This is no problem if you upgrade your accessory drive to a Holley LS-based system. These accessory drives have been available for the LT engines for a while now, but the newest version, the Mid-Mount, changes everything. The other Holley accessory drives are more like the factory systems, with brackets that bolt to the block and heads, using an LS-style water pump. The Mid-Mount system started from scratch and the entire system bolts to the block via the water pump bolts. Six bolts hold the whole thing in place, and it is spectacular.

Holley LT Mid Mount layout

This is the entire kit laid out on the workbench. It is very simple kit, which is nice because if you have to take it off in a parking lot to fix your vehicle, all you need to remove are six bolts and you are done...not including hoses of course.

The water pump housing is a custom designed unit for Holley. It uses a replaceable water pump turbine that bolts into the main housing, which is cast aluminum. All of the accessories mount directly the new housing, nothing mounts to the heads. This does several things, mainly it keeps everything neat and tidy, close to the engine, so the Mid-Mount fits in more applications with all the accessories, including air conditioning and power steering. The accessories are no longer the widest part of the engine; now the exhaust is. That is a big deal for swaps, completely eliminating the clearance issues that so commonly make LS and LT swaps grind to a halt.

We had the opportunity to install one of these systems onto a 2015 L83 5.3 Gen-V LT-series engine that is destined for an upcoming build, which features an STS turbo and Tremec TKX 5-speed fitted into a 1962 Mercury Comet station wagon. The beauty of this design is not only the compact fitment and great looks, but also that you can pull the whole system with six bolts for servicing the engine. That beats anything else in terms of convenience.

The kit we selected was the master kit in black, which comes with all the accessories including a Sanden SD7 A/C compressor and an ATI Super Damper. There are options without all the components, some of the components, stock pulley, etc. Our kit also came with black machined aluminum covers for the pulleys, which make it even better looking. If you use this kit with an LT car intake and throttle body, then you will need the supplied throttle body angle adapter, which alters the throttle body angle so that you don’t have clearance issues. Basic hand tools are all you need to install the entire system, with the exception of the ATI balancer, which requires Torx+ bits, which are thicker than a standard Torx. You also need a crank removal tool that fits LS/LT cranks, and an installation tool for LS/LT engines, which do not come in most crank pulley installer kits. You can install the entire system in about two hours on an engine stand, though it might take a little longer if your engine is already in the vehicle due to access limitations.

Holley LT Mid Mount steam port plug

Because we are installing this on a Gen-V LT engine, which has no steam lines, we installed the supplied plug with some liquid thread sealant. You could use this port for a temperature sender to run your gauges with a miniature temperature sender.

Holley Mid-Mount LT temp sender

Next, we installed the original temperature sender from the original water pump. This connects to the ECM.

Holley mid-mount LT water pump into housing

Next, we installed the water pump into the housing. This requires the use of this metal gasket, which is reusable.

Holley Mid-Mount LT water pump locating tab

The water pump has a locating tab that must be indexed correctly on the housing.

Holley Mid-Mount LT ball-end hex key warning

Do not use a ball-end hex key on the mounting bolts to torque them, ball-end keys can strip the head.

Holley mid-mount LT original crank bolt removal

Removing the original crank bolt requires heating up the head with a propane torch. The bolt has red threadlocker on the backside of the flange, which locks it onto the pulley. A couple of minutes of heat and it comes out easily.

Holley Mid-Mount LT crank pulley removal

All LS and LT engines require a special hook-jaw puller to remove the pulley. You need the longest forcing rod to slide into the crank snout, as the LT cranks are very deep.

Holley Mid-Mount LT ATI Damper assembly

Our kit came with the new ATI damper, which has to be assembled. There are two indent marks which must be lined up in order for the damper to balance.

Holley Mid-Mount ATI Damper 2

We slipped the hub into the damper ring and bolted it down using the supplied Torx bolts using a Torx+ bit, then installed the assembly to the crank using an installer tool.

Holley Mid-Mount LT Damper/Pulley Install

The kit comes with a new balancer bolt, which is required for all LS and LT engines. You cannot reuse the original torque-to-yield crank bolt. The actual pulley gets installed AFTER the damper is torqued down to factory specs (37 ft-lb to seat, then an additional 130 degrees)

Holley Mid-Mount LT water pump gasket

No paper gaskets here, instead you get reusable metal gaskets for the water pump. The bolts can be pre-installed in the pump housing as the gasket will retain them in position.

Six M8 bolts (13mm socket) hold the housing to the block. These bolts are torqued to 18 ft-lb.

Holley Mid-Mount LT thermostat and water neck

Make sure that the thermostat is clocked correctly into the water neck as shown. There is a little notch in the neck that matches the rubber block on the thermostat.

Holley Mid-Mount LT Coolant Ports and Swivel Fittings

Yet another trick feature of the mid-mount design are the coolant ports. There are two on the side and two directly below facing down, so you have all kinds of options for getting the coolant hoses routed. You can use the supplied straight fittings or opt for a set of swiveling 90-degree fittings.

Holley Mid-Mount LT coolant port plugs

The kit comes with two plugs to plug the unused holes. We opted for the side exit ports and blocked the lowers. The plugs are 9/16” hex, so we just made a tool with a 3/8” bolt and two nuts (the nuts and bolts hex are 9/16”.) Don’t forget the liquid thread sealant.

Holley LT Mid-Mount Alternator Install

Next, we installed the new 150-amp alternator using the supplied bolts.

Holley Mid-Mount LT Power Steering 1

The power steering pump requires a little assembly before being installed onto the housing. The output fitting is a hardline that uses a banjo fitting. There are two washers used with this style of fittings, and these are not reusable. One washer goes under the fitting and the pump…

Holley Mid-Mount LT Power Steering 2

…and the second washer goes under the head of the banjo bolt.

Holley Mid-Mount LT Power Steering 3

Then the bolt is tightened with a hex key.

Holley Mid-Mount LT Power Steering 4 Pulley Installation

You need a pulley installation tool to install the pulley onto the pump. Sometimes these go on easy, and sometimes they fight a bit. If you need the extra torque to install the pulley, simply bolt the pump to the engine so you can finish installing the pulley.

Holley Mid-Mount LT Power Steering Pump Installation

The pump installs to the mid-mount housing with M8 bolts (13mm socket). Make sure the pulley is flush with the pump shaft for proper alignment.

Holley Mid-Mount LT Air Conditioning 1

We pre-installed the lower bolt on the AC compressor, just lightly threaded in. Do not tighten it yet.

Holley Mid-Mount LT Air Conditioning 2

The bolt slides into the housing as shown. This keeps the install clean and easy to service.

Holley Mid-Mount LT Air Conditioning 3

The outer bolt installs from the rear of the housing. Once both are threaded in, they can be torqued to 18 ft-lb.

Holley Mid-Mount LT Belt Tensioner Installation

The last component is the tensioner, which uses a single button-head fastener and washer that is torqued to 18 ft-lb.

Holley Mid-Mount LT Kit Installed

This is the finished drive with the supplied belt installed. The entire process only takes a couple hours from start to finish.

Holley Mid-Mount LT Optional covers

Our kit had the optional trim covers, which install to the tensioner, AC clutch, and alternator.

Holley Mid-Mount LT Complete with Covers

With the covers installed, our engine is ready for service! Note how tight to the engine the accessories are. This fits nearly every chassis you could want to swap an LS or LT engine into.


Holley Mid-Mount Accessory Drive Installation onto GM LS Engines

The LS engine family was the inspiration behind Holley's accessory drive systems. Follow the installation of the Mid-Mount Accessory Drive Kit onto this truck 5.3L V8.

Holley Mid-Mount Accessory Drive Installation onto Small-Block Chevrolet

It isn't just the modern engines that benefit from the Mid-Mount Accessory Drive. Follow along with the installation of the kit onto this 377ci small-block Chevrolet. Kits for big-block Chevrolet are available, too!

Holley Mid-Mount Accessory Drives for Gen III Hemi

The Gen III Hemi can benefit from the compact design of the Mid-Mount Accessory Drive Kit, for both VVT and non-VVT engines! Be sure to check out our installation guide video as well.


12 Posts