LS Swapping the 1964-67 GM A-Body Intermediates (photos)
The introduction of the A-body in 1964 saw the debut of some of the best loved muscle cars. These included the Chevelle/Malibu, Skylark, Tempest/Lemans, Cutlass/F-85, and El Camino, many of which are just crying out for an LS swap.
1. The Dawn of the A-Body
1964-1967 saw the introduction of the GM A-body mid-size car platform with the Chevelle, Le Mans, Malibu, Cutlass, Skylark, El Camino, Tempest, and other models. These cars originally came equipped with sixes, or various V8 engines of up to 400 cubic inches in size, but their nose heavy weight distribution was detrimental to their handling. They all have plenty of room up front though, so there is little worry about fitting an modern LS-based engine under the hood. If you have a classic GM intermediate and want more power and better handling, ditch the aging iron engine in favor of contemporary aluminum GM LS powerplant. The parts are readily available to allow for a straightforward LS install. Much of the information here is also applicable to the 1961-63 Buick, Olds, and Pontiac compacts, as well as the 2nd generation A-body from 1968-72.
2. Engine Mount Plates
The first step on any LS engine conversion is getting the engine properly positioned in the chassis to bolt to the transmission, allowing the correct driveline angle, and room for accessories and exhaust routing. There are a number of vendors who offer engine mount plates that bolt right in to the 64-67 A-body cars to make LS engine mounting a breeze. Companies like Hooker and Hedman offer mount plates that clear the stock power steering boxes and maintain the same transmission mating location, in case the stock transmission unit is used. On the other hand, companies like Dirty Dingo Motorsports have developed fully adjustable mount plates to allow the engine to be positioned virtually anywhere in the engine bay for better weight distribution.
3. Oil Pan Options
Oil pan clearance is the key issue on any LS swap, and is something to keep in mind before getting too deep into your LS conversion. Most factory LS pans have the sump and oil pump pickup on the front of the motor. There are numerous oil pans on the market that work, but you want to make sure it is a high clearance pan so it doesn't hang below the frame crossmember. Most swappers opt for Holley's 302-2 LS retrofit oil pan with good results, but the Canton Racing baffled LS 15-274 road race pan, Autokraft LS Pan Package, and Moroso High Clearance Oil Pan are all worthy alternatives.
4. Transmission & Trans Crossmember
GM gave us all a gift when they used the same bellhousing bolt pattern as the old Chevy small block, so practically any transmission will bolt up to it. You will need a Chevy tranny though, or a dual pattern one (like the 200-4R), the Buick-Oldsmobile-Pontiac pattern doesn't work. Thankfully there are a number of modern transmission options available that fit the 64-67 A-body platform too. Hedman offers a variety of transmission mounting options for using the T-56 6-speed, as well as the 4L60E/4L65E automatic transmissions. Hooker also makes a nice modular transmission crossmember that can directly accept Tremec manuals gearboxes and 4L80E/4L85E automatics right out of the box, but is also compatible with 4L60E/4L65E/4L70E, TH400, or 200R4 with their add-on adapters. Similarly, BRP Hot Rods has transmission mount kits for all of the previously listed transmissions with the addition of the TR-6060 and 6L80E/6L90E. The one pictured is a fully adjustable unit from Speedtech. You will need a simple hub adapter to make up for the 1/2" shorter crankshaft if you plan on using an old school automatic and torque converter, like this, and the correct LS flex plate.
5. Exhaust
Exhaust setups can be the most difficult part of engine swaps, but companies such as Hedman, Hooker, and BRP Hot Rods have you covered for your exhaust needs. Each manufacturer has a variety of header options for the A-body chassis in both mid-length and long-tube designs. Headers are available with primary tube size ranging from 1-3/4" to 2" in both straight and stepped configurations, and feature 3" collectors. From the headers back, individuals have the option to build their own custom exhaust setup, or can opt for Hooker's complete 2.5" or 3" exhaust system with mufflers that will bolt right up without any hassle.
6. Fueling & Cooling
To support a fuel-injected LS engine, an upgraded fuel system will need to be used, or you'll have to modify the motor to use a carburetor. Perhaps the easiest route for fueling is a replacement fuel tank from places like BRP Hot Rods, Rick's Tanks, or Rock Valley that incorporate an in-tank fuel pump/module made specific for the output of your LS engine.
To keep your new LS engine cool, it is recommended that a new LS specific radiator be installed but that needn't be expensive. Drop-in radiators with properly positioned outlets are available from companies such as Dewitts and BRP. Their aluminum, dual-core radiator setups come with cooling fans/shroud and your choice of a transmission cooler for those running an automatic transmission. These radiator kits are roughly 30-40% more efficient than the stock radiator.
7. Wiring & ECM
There are a lot of options for wiring your new LS-based engine into the car. GM sells a complete wiring harness and ECM kits that includes an electronic drive-by-wire pedal assembly for use on all 03+ Generation IV engine. Similarly, there are numerous companies like Current Performance Wiring and Speartech who are able to build wiring harnesses specific to your needs. Options are almost endless as there are stand alone kits that allow for coil pack usage on a carbureted engine, and electronic transmissions without the traditional ECU to control it. If you are handy with wiring looms, there is always the option of building your own wiring harness for your application. With the ability to easily flash ECMs, just about any company that specializes in LSX tuning can create a map specific for your engine and get you rolling in no time.
For help servicing and maintaining your LS powered ride, check out the how to section of LS1Tech.com