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We recently rebuilt a 2003 LM7 5.3L Gen III LS for a turbo swap into a 1966 Cadillac. It was an ideal choice for several reasons – LS motors are plentiful, they’re affordable, and it’s relatively easy to get them to make the power needed to motivate a hefty vintage behemoth like this car. At the same time, LS engines also have the advantage of compact overall dimensions, which is helpful anytime you’re doing an engine swap.
You may be thinking, “A ‘60s Caddy is huge – you could put a 5-foot-wide engine under that hood!” But while the car itself is 20-feet long, the engine bay is not as roomy as you might think. In fact, it has hardly any room at all; the inner fenders are huge, the firewall is cluttered, and the chassis doesn’t particularly like LS engines. So, keeping the engine tight and compact was critical.
Our turbo LS motor will ultimately provide enthusiastic motivation for this rather hefty machine. Despite the Caddy's monstrous exterior dimensions, underhood space is tighter than you might think, making it necessary to slim our LS down as much as possible. For most swaps, an aftermarket accessory drive is the most effective way to trim those vital inches.
When trying to slim down the dimensions of an LS engine for swapping, the first and best target is typically the accessory drive system, which mounts the alternator, air-conditioning compressor, and other belt-driven components to the front of the engine. Stock LS accessory drives rarely fit well, and they leave a lot to be desired in the looks department. For most applications, bringing accessories as far inboard as possible gives you the most room under the hood.
Holley has multiple accessory drive options for LS and LT engines, in high- mid- and low-mount designs. For most car builders, the mid-mount has become the go-to version. Instead of relying on the block and heads for mounting multiple brackets, the Holley mid-mount drive eliminates all the secondary bracketry.
Every component—water pump, alternator, AC compressor, and power-steering pump – mount directly to the water pump housing, which is made of cast aluminum. No more AC compressor interfering with motor mounts, or power-steering pump hitting the frame. This not only looks great and keeps the accessories the same width as the block, it also makes servicing your engine easier.
And with this configuration, the water pump is no longer a cumbersome hunk of aluminum you have to wrestle with. Instead, it’s only about 8-inches in diameter and it’s mounted with six bolts – you just replace the pump drive itself. You can even take the entire accessory drive off the block with just six bolts.
Click Here Now to see Holley's complete line of LS accessory drive components and kits
Holley LS accessory drive kits are available in high-, mid-, and low-mount versions, so you can get the setup that works best for your particular combination.
The overall width of this drive kit is just a bit bigger than the engine itself. The widest section is the heat hoses, which can be located in a side or straight-down exit, giving you options for hose routing. Holley really did think of everything when they designed this system. The kit comes with all the parts and pieces you need, or you can buy components separately. If you have the accessories themselves, you can save some cash by ordering the mounts alone. If you order a master kit like we did, you get everything, including some trick looking covers for the pulleys and tensioner.
We installed a new reuseable crank bolt from Earl’s so we didn’t have to mess with the single-use stock TTY bolt. You do need a couple of specialty tools. First, you need a crank pulley removal tool. These are LS/LT specific, requiring a much longer push bar, as the crank snout is very deep. Also required is a crank pulley installer – essentially grade-8 all thread and a couple of nuts and washers – and a power-steering pulley installer. The crank installation tool can be hard to find locally, but you can make one or order it online. The other tools can typically be rented at your local parts store.
Our kit went on quickly and easily; the entire assembly took about three hours from start to finish with the engine on a stand. The Holley mid-mount is a transformative piece. It can make an old crusty truck engine look shiny and new, especially in the satin black finish option, which is what we used. We can’t wait to get this 5.3 in the Caddy, toss 8 psi of boost on it, and send it.
The system uses the OE water pump gaskets, which also hold the bolts in place for assembly.
Just six bolts hold the main water pump housing to the block, and everything bolts on from there.
We installed the water pump using the supplied button-head Allen fasteners. You need to be careful and not use rounded “pivot” style Allen wrenches, as they do not have the engagement needed and will strip the bolts out.
We opted for the basic crank pulley, but a Super Damper option is available. The crank installation tool is quite simple, but it takes some effort to get the crank pulley onto the crank snout.
When assembling the water neck, don’t forget to line up the thermostat with the notch in the neck.
Heater hose routing is greatly simplified using the side and bottom ports on the main housing. The kit comes with hose barbs and pipe plugs so you have everything you need to complete the installation.
To get the power steering high-pressure line in the right position, a hardline gets mounted with a banjo bolt to the pump.
You can install the pulley on or off the engine. Just make sure to use a proper installation tool and make sure the pulley is flush with the shaft.
Without the pulley installed, the pump bolts are a bit easier to access.
The AC compressor is a Sanden SD7 unit, which requires the inside bolt to be threaded into the compressor BEFORE installation. The bolt is just lightly threaded in.
The reason the bolt is pre-installed is because you can’t install it once the compressor is mounted in the housing. The inside bolt slides into the channel as shown here.
A new tensioner is included, and it installs with a single button-head bolt. You can get optional covers for the idler and pulleys, but the tensioner cover has to be removed to install or remove the belt.
The finished product looks great and trims the necessary inches off the motor's width. The Holley kit went on quickly and easily; the entire assembly took about three hours start to finish.
Click Here Now to see Holley's complete line of LS accessory drive components and kits
