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 Nova without modifications. While there are quick and expensive ways to mount an alternator, power steering pump, and air conditioning compressor, our goal is to show you how to do this while watching that budget. The good news is that you can get what you need without having to spend big dollars. It all depends on how trick you want to get.
GM Accessory-Drive Layouts
All 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 the system was designed for a truck, the original LS1 Camaro/Firebird platform, or a Corvette. As for the A/C, all three systems mount the A/C pump in generally the same spot, but the mounts are not interchangeable.
The Corvette drive is the tightest to the front of the engine and places the alternator on top 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 was used on the Camaro/Firebird and early CTS-V Cadillacs that employ a harmonic balancer that 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 third orientation is the truck/SUV that uses the deepest balancer, pushing the accessory drive the 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. It may also present hood clearance problems on cars with low hood lines. It cannot be used with any passenger-car LS EFI intake manifold because of interference between the throttle body and the idler pulley.
We also discovered a glitch where an F-car-style factory alternator bracket bolts to an aluminum 5.3L block (and we'll assume most other aluminum blocks), but when we tried to bolt it to an iron 6.0L block, there was one missing bolt location on the block and another that was not drilled or tapped. It's unclear whether this missing bolt hole extends to all iron blocks. Roger Kunkel sent us a photo of his solution based on an F-car alternator 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 accessory drive, 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 the factory-recommended procedure for torquing the factory balancer bolt. The spec requires an initial torque of 37 ft-lb and then using the torque angle method to tighten the 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 the Corvette, Camaro/Firebird, and truck accessory drives. We've listed two different ways of measuring 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 of the balancer/pulley (overall depth), which can be used to identify a balancer not mounted 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.
Balancer (Inches) / Depth Of Balancer
(On Engine) (Inches)
Corvette / 3 7/16 / 2 1/8
Camaro / 3 13/16 / 2 15/16
Truck / 4 3/8 / 3 11/16
What Fits--And What Doesn't!
The main focus of this story is to give you an idea of which factory-available accessory drives can be used for engine swaps. But just as important is which factory configurations don't fit. The difficulty with generic information like this is it all has to be qualified with a bold-faced "it depends" because of the multiple fore/aft locations for LS engines in muscle car chassis. Not all engine conversion mounts place the engine in the same location, so be aware of this major variable. For example, the Street & Performance, ATS, and Morrison mounts (and probably others) locate the engine in the same position, but the Hooker mounts (for early Camaros and '68 to '72 Novas as an example) locate the engine roughly an inch farther aft. The BRP mounts raise the engine up and also push it much farther forward. In the interest of available space, we'll save these details for a later story. In this sidebar, we deal mainly with Gen III/IV alternator and power steering packages. As for the factory A/C pumps, in most cases the factory A/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 Carlos are based on an A-body chassis, these cars should also be similar to Chevelle fitment details. For all these cars, the factory Corvette accessory drive will clear all suspension and steering components. The downside is that this system tends to be hard to find and expensive. Camaro-based accessory drives don't fit Chevelles because the alternator crashes 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 shy away 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 is snug. If you're using the Hooker mount kit, you will have to notch the engine crossmember 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're fortunate enough to own one of these systems.
The most important change for the second-generation ('70 to '81) Camaro/Firebird is that these cars converted to front steer, moving the steering box in front of the axle centerline like a Chevelle. This makes fitting the F-car LS1 accessory drive, with its low alternator, tight. It will clear the steering box, but clearance is minimal depending on which engine mounts are used. The Corvette-style drive will clear everything, while the truck system will not fit under the stock hood line. As with the other body styles, the A/C will only work if it is relocated up high on the passenger side.
For those considering an LS engine into an '82 to '92 Camaro, the F-car accessory drive will bolt in without serious modifications except that the factory A/C compressor will only clear with a notch in the engine crossmember. In terms of other later-model swaps, it appears that swapping an LS-style engine into a C4 also has significant merit. As for an accessory drive, it appears that a Corvette (Y-car) front dress will work.
GMPP Kits
Accessory 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 these systems 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 the necessary 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 drives but is actually an '06-style Cadillac CTS-V arrangement. The catalog calls out the 19155067 system as designed for the LS2 and LS7 engines, but it will work on most all Gen 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 those who don't need an A/C pump, there's a rumor that GMPP will soon release a new system without 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 cost more 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 use the original Saginaw Type I pump with its integral metal fluid reservoir, while passenger cars use the newer Type II power steering pumps. There are also two different Type II pulley shaft diameters at 0.660 and 0.750 inch. Some information points to the smaller diameter as used on Corvettes, but we've purchased several passenger-car Type II pumps that use the 0.660-inch shaft diameter.
The factory parts necessary to mount a plastic factory remote reservoir system are expensive at around $100.00, and the part numbers can be found on Kwik Performance's website under Tech Tips, but there are alternatives. You can create a custom remote reservoir using AN lines and fittings for roughly the same price. If you are building your own remote reservoir system, the return line should be a minimum of 5/8-inch id, while the high-pressure side is normally a -6 AN.
The last variable is power steering pump pulleys. We've found there are many different pulley diameters, depending on the application. A smaller pulley offers more clearance, but it also increases pump speed, especially at idle. Changing pulley diameters will also require a new serpentine belt.
Kwik Performance
The problem with most aftermarket accessory drives is the entire system ends up costing a lot of money--anywhere from $850.00 to $2,500.00, so we began searching for a low-cost alternative, which turned up a new company called Kwik Performance. As a SEMA member, Kwik had access to GM's CAD drawings of the Gen III/IV engines and used these specs to create a new generation of accessory drive pieces that solve many of the problems associated with swapping a Gen III engine into early muscle cars. Kwik created three kits based on balancer dimensions for trucks, F-cars, and Corvettes. One big advantage of this idea is it eliminates the purchase of a new balancer. So if you have a truck engine, you can purchase a Kwik alternator and power steering mount kit for $287.00 that will bolt directly to your existing engine and clear the chassis. We did the math to get an idea what the total cost would be to convert a truck accessory drive for use in an early Chevelle. The kit allows you to retain the use of a truck or F-car-style alternator, and the truck accessory drive will require a Type II power steering pump and pulley, but that's the only major requirement. You'll also need a power steering pump pulley. We found several at the junkyard on '90s V-8 Cadillacs for $5.00 each. A new factory reservoir package will run another $100.00 , so we decided to do a remote reservoir that can use AN fittings with a nice aluminum tank from Summit Racing. Street & Performance, among many other companies, offers custom-made power steering hose kits for your application.
Description / PN / Source / Price
Kwik alternator, P/S drive, truck / K10168 / Kwik Performance / $287.00
A-1 Cordon P/S pump / 20878 / Rock Auto / $45.79
Typical serpentine belt / K060775 / Rock Auto / $26.79
Summit aluminum remote reservoir / 340202 / Summit Racing / $80.95
16 mm to AN -6 / 991955 / Summit Racing / $6.25
Press in to -8 AN / call / Street & Performance / $15.00
Summit 3-foot-length -8 hose / 230803 / Summit Racing / $15.95
Summit 3-foot-length -6 hose / 230603 / Summit Racing / $14.95
Power steering pulley / 1636993 / Used / $5.00
Painless alternator adapter / 30705 / Summit Racing / $25.95
Total (your price may vary) / $523.63
General Parts List
Description / PN / Source / Price
March alternator, P/S / 20050 / March Performance / $2,395.00
Concept One alternator, P/S, A/C / LSV01M / Concept One / $2,375.00
Billet Specialties alternator, P/S / 13405 / Summit Racing / $2,089.95
Street & Performance alternator, P/S / N/A / Street & Performance / $958.35
GMPP LS1/LS6 accessory drive / 19155066 / Scoggin-Dickey / $825.85
GMPP LS2/LS7 accessory drive / 19155067 / Scoggin-Dickey / $825.85
Kwik alternator, P/S drive, Camaro / K10167 / Kwik Performance / $287.00
Kwik alternator, P/S drive, Corvette / K10166 / Kwik Performance / $287.00
Kwik A/C bracket, F-car / K10156 / Kwik Performance / $197.00
Kwik A/C bracket, Vette / K10143 / Kwik Performance / $197.00
Kwik A/C bracket, truck / K10163 / Kwik Performance / $197.00
Car Shop alternator bracket and alternator / 9998 / Car Shop Inc. / $550.00
A1 Cardone water pump, F / 58563 / Rock Auto / $92.99
GM P/S pulley (0.750 shaft) / 10166335 / Burt Chevrolet / $44.00
Dorman Corvette balancer / 594115 / Rock Auto / $73.79
Dorman F-car balancer / 594127 / Rock Auto / $51.89
Bosch truck alternator, 105 amps / AL8730N / Rock Auto / $155.79
GM LS1 balancer bolt / 12557840 / Scoggin-Dickey / $4.44
GM balancer bolt washer / 12600525 / Scoggin-Dickey / $16.66
ARP balancer bolt and washer / 234-2503 / Summit Racing / $27.95
SOURCES
American Touring Specialties / Kwik Performance
Las Vegas, NV / Springfield, MO
702/245-6305 / 417/955-1467
T56kit.com / kwikperf.com
Billet Specialties / March Performance
La Grange, IL / Naples, FL
800/245-5382 / 888/729-9070
billetspecialties.com / marchperf.com
BRP Muscle Rods / Painless Wiring
Cumming, GA / Fort Worth, TX
770/751-0687 / 817/560-8324
brphotrods.com / painlessperformance.com
Burt Chevrolet / Rock Auto
Englewood, CO / Madison, WI
800/345-5744 / 866/762-5288
burt.com / rockauto.com
Car Shop / Street & Performance
Moline, IL / Mena, AR
309/797-4188 / 479/394-5711
carshopinc.com / hotrodlane.cc
Concept One Pulley Systems / Summit Racing
Cumming, GA / Akron, OH
877/785-5397 / 800/230-3030
c1pulleys.com / summitracing.com
GM Performance Parts
Warren, MI
800/577-6888
gmperformanceparts.com
This is the stock configuration for the Camaro/Firebird accessory drive found on '98 to '02 F-cars minus the A/C pump. The easiest way to spot this design is by the power steering pump on top on the driver side with the alternator below. This is also the drive arrangement for the GMPP kit PN 19155066.