LS Engine Pulleys - LS Accessory-Drive Swap Guide Bolting A Gen III/IV Engine In To An Early GM Muscle Car Isn't Difficult, But There Are Some Shortcuts That Can Save You Time, Money, And Hassle... By Jeff Smith Photography by Jeff Smith, Roger Kunkel, Troy Matos Accessory drives have always been a hassle when it comes to engine swapping, but armed with this information, your choices become much easier and less expensive. One of the hottest engine swaps in our world right now is the Gen III/IV (or LS, if you prefer) engine transplanted into a '60s or '70s GM muscle car. These engines not only are more powerful than the old Gen I small-blocks, but they're also lighter, don't leak, are easier to work on, and are far more efficient. It's everything a car crafter could want, but swappers have discovered that these engines don't bolt in to a Camaro, Chevelle, or
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7/27/2019 LS Engine Pulleys - LS Accessory-Drive Swap Guide
Bolting A Gen III/IV Engine In To An Early GM Muscle Car Isn't Difficult, But There AreSome Shortcuts That Can Save You Time, Money, And Hassle...
By Jeff SmithPhotography by Jeff Smith, Roger Kunkel, Troy Matos
Accessory drives have always been a hassle when it comes to engine swapping, butarmed with this information, your choices become much easier and less expensive.
One of the hottest engine swaps in our world right now is the Gen III/IV (or LS, if youprefer) engine transplanted into a '60s or '70s GM muscle car. These engines not onlyare more powerful than the old Gen I small-blocks, but they're also lighter, don't leak,are easier to work on, and are far more efficient. It's everything a car crafter could want,but swappers have discovered that these engines don't bolt in to a Camaro, Chevelle, or
7/27/2019 LS Engine Pulleys - LS Accessory-Drive Swap Guide
Nova without modifications. While there are quick and expensive ways to mount analternator, power steering pump, and air conditioning compressor, our goal is to showyou how to do this while watching that budget. The good news is that you can get whatyou need without having to spend big dollars. It all depends on how trick you want toget.
GM Accessory-Drive LayoutsAll factory GM systems place the alternator and power steering pump on the driver side
with the A/C compressor mounted low on the passenger side driven by a separate belt.Within this basic layout, there are three significant variations based on whether thesystem was designed for a truck, the original LS1 Camaro/Firebird platform, or aCorvette. As for the A/C, all three systems mount the A/C pump in generally the samespot, but the mounts are not interchangeable.
The Corvette drive is the tightest to the front of the engine and places the alternator ontop with the power steering pump underneath. This arrangement is wider at the top,offering maximum clearance toward the bottom of the engine. The next system wasused on the Camaro/Firebird and early CTS-V Cadillacs that employ a harmonic balancerthat projects out farther than the Corvette. This drive system places the power steering
pump on top on the driver side with the alternator positioned underneath. The thirdorientation is the truck/SUV that uses the deepest balancer, pushing the accessory drivethe farthest forward on the engine. The truck orientation is the narrowest and tallest of the three drives with the alternator up top and the power steering pump underneath. The truck system is the most common of the three but is the least visually attractive. Itmay also present hood clearance problems on cars with low hood lines. It cannot be usedwith any passenger-car LS EFI intake manifold because of interference between thethrottle body and the idler pulley.
We also discovered a glitch where an F-car-style factory alternator bracket bolts to analuminum 5.3L block (and we'll assume most other aluminum blocks), but when we triedto bolt it to an iron 6.0L block, there was one missing bolt location on the block andanother that was not drilled or tapped. It's unclear whether this missing bolt holeextends to all iron blocks. Roger Kunkel sent us a photo of his solution based on an F-caralternator rear mount location, leaving the missing bolt out of the front mount.
While we have not performed this swap, it does appear that a Gen III LS1 F-car accessorydrive, for example, will bolt on to the later LS2 or LS3 engines (Gen IV) as long as the F-car balancer is used. Also keep in mind that if you change balancers, you must follow thefactory-recommended procedure for torquing the factory balancer bolt. The specrequires an initial torque of 37 ft-lb and then using the torque angle method to tightenthe bolt an additional 140 degrees. This technique applies to the one-time-use torque-to-yield GM bolt. If you plan on lots of swaps, consider going to a reusable ARP bolt.
Harmonic Balancer Depths The following chart lists the dimensions of the three different pulley depths used on theCorvette, Camaro/Firebird, and truck accessory drives. We've listed two different ways ofmeasuring these, both with the balancer on the engine and on the bench. The depth of balancer dimension is measured from the rear of the balancer hub to the leading edge ofthe balancer/pulley (overall depth), which can be used to identify a balancer notmounted on an engine. We also included the depth from the front cover to the front of the balancer if it is installed on the engine.
7/27/2019 LS Engine Pulleys - LS Accessory-Drive Swap Guide
What Fits--And What Doesn't! The main focus of this story is to give you an idea of which factory-available accessorydrives can be used for engine swaps. But just as important is which factoryconfigurations don't fit. The difficulty with generic information like this is it all has to bequalified with a bold-faced "it depends" because of the multiple fore/aft locations for LSengines in muscle car chassis. Not all engine conversion mounts place the engine in thesame location, so be aware of this major variable. For example, the Street &Performance, ATS, and Morrison mounts (and probably others) locate the engine in thesame position, but the Hooker mounts (for early Camaros and '68 to '72 Novas as anexample) locate the engine roughly an inch farther aft. The BRP mounts raise the engineup and also push it much farther forward. In the interest of available space, we'll savethese details for a later story. In this sidebar, we deal mainly with Gen III/IV alternatorand power steering packages. As for the factory A/C pumps, in most cases the factoryA/C compressor will not clear the chassis without notching the engine crossmember.
The '64 to '72 GM A-body cars include Chevelle/Malibu, Pontiac Tempest/Le Mans/GTO,Buick Skylark/GS, Olds Cutlass/F-85, and since the early '70 to '72 Chevy Monte Carlosare based on an A-body chassis, these cars should also be similar to Chevelle fitmentdetails. For all these cars, the factory Corvette accessory drive will clear all suspensionand steering components. The downside is that this system tends to be hard to find andexpensive. Camaro-based accessory drives don't fit Chevelles because the alternatorcrashes into the steering box. The truck drives will work if modified with a 5-inch-diameter power steering pump pulley to clear the steering box, but most car crafters shyaway from this system for aesthetic reasons, since the alternator sits very high.
For early '67 to '69 Camaros/Firebirds and '68 to '74 Novas with a factory front subframe,either the F-car LS1-style or the Corvette drives will fit, although the F-car alternator issnug. If you're using the Hooker mount kit, you will have to notch the enginecrossmember to clear the alternator. The truck accessory drives are way too tall to clear
the low hood line while, again, the Corvette accessory drive will bolt right on if you'refortunate enough to own one of these systems.
The most important change for the second-generation ('70 to '81) Camaro/Firebird is thatthese cars converted to front steer, moving the steering box in front of the axlecenterline like a Chevelle. This makes fitting the F-car LS1 accessory drive, with its lowalternator, tight. It will clear the steering box, but clearance is minimal depending onwhich engine mounts are used. The Corvette-style drive will clear everything, while thetruck system will not fit under the stock hood line. As with the other body styles, the A/Cwill only work if it is relocated up high on the passenger side.
7/27/2019 LS Engine Pulleys - LS Accessory-Drive Swap Guide
For those considering an LS engine into an '82 to '92 Camaro, the F-car accessory drivewill bolt in without serious modifications except that the factory A/C compressor will onlyclear with a notch in the engine crossmember. In terms of other later-model swaps, itappears that swapping an LS-style engine into a C4 also has significant merit. As for anaccessory drive, it appears that a Corvette (Y-car) front dress will work.
GMPP KitsAccessory drives are some of the most difficult components to design on an engine, and
no one does it better than the factory. GM spends thousands of dollars ensuring thesesystems are not only reliable but also quiet and easy to repair. To take advantage of this,GM Performance Parts now offers two different accessory-drive kits that offer all thenecessary components to bolt on a complete system to the front of a Gen III/IV engine. The 19155066 kit is configured like the older F-car or Camaro/Firebird LS1 engine drivesbut is actually an '06-style Cadillac CTS-V arrangement. The catalog calls out the19155067 system as designed for the LS2 and LS7 engines, but it will work on most allGen III/IV engines as far as we know. This system is based on a Corvette configuration.Both kits include an A/C compressor along with all mounts, bolts, and belts. For thosewho don't need an A/C pump, there's a rumor that GMPP will soon release a new systemwithout the A/C compressor to trim the price even further. The best part about the
current systems is the $825.85 price tag. We priced the parts individually and the costmore than doubles, so the value is already high.
Power Steering Pumps There are two types of power steering pumps used on the Gen III/IV engines. Trucks usethe original Saginaw Type I pump with its integral metal fluid reservoir, while passengercars use the newer Type II power steering pumps. There are also two different Type IIpulley shaft diameters at 0.660 and 0.750 inch. Some information points to the smallerdiameter as used on Corvettes, but we've purchased several passenger-car Type IIpumps that use the 0.660-inch shaft diameter.
The factory parts necessary to mount a plastic factory remote reservoir system areexpensive at around $100.00, and the part numbers can be found on Kwik Performance'swebsite under Tech Tips, but there are alternatives. You can create a custom remotereservoir using AN lines and fittings for roughly the same price. If you are building yourown remote reservoir system, the return line should be a minimum of 5/8-inch id, whilethe high-pressure side is normally a -6 AN.
The last variable is power steering pump pulleys. We've found there are many differentpulley diameters, depending on the application. A smaller pulley offers more clearance,but it also increases pump speed, especially at idle. Changing pulley diameters will alsorequire a new serpentine belt.
Kwik Performance The problem with most aftermarket accessory drives is the entire system ends upcosting a lot of money--anywhere from $850.00 to $2,500.00, so we began searching fora low-cost alternative, which turned up a new company called Kwik Performance. As aSEMA member, Kwik had access to GM's CAD drawings of the Gen III/IV engines and usedthese specs to create a new generation of accessory drive pieces that solve many of theproblems associated with swapping a Gen III engine into early muscle cars. Kwik createdthree kits based on balancer dimensions for trucks, F-cars, and Corvettes. One bigadvantage of this idea is it eliminates the purchase of a new balancer. So if you have a
7/27/2019 LS Engine Pulleys - LS Accessory-Drive Swap Guide