LS Swapping a C3 Corvette
The powerful third generation Corvette burst onto the scene in 1968 with many improvements over the outgoing model. That said, the Corvette really took a turn for the worse in the early 1970's with the federal government's enforcement of stricter emission standards. As a result, many of the C3 Corvettes made during the 15-year production run could greatly benefit by swapping out their anemic engines for some modern LS power.
1. Engine & Transmission Mounts
The time has never been better to swap LS power into your classic C3 Corvette with a Muscle Rod kit from vendors such as BRP HotRods Inc and LSX Everything supplying swap kits to make installation a breeze. Kits provide motor mounts and frame brackets to fit LS series engines, as well as transmission mounts, transmission cross member, and all necessary hardware to allow for a trouble-free powertrain swap. Most individuals prefer to ditch their old 3 or 4-speed manual transmission in favor of a new Tremec T-56 or TR-6060 6-speed gearbox which simply requires an LS to Tremec bell housing adapter available from just about any speed shop. Those wishing to keep their original Turbo-Hydramatic auto trans can make things work with a simple flexplate and crank extender kit.
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2. Oil Pan
Clearance for the oil pan of an LS engine can be quite difficult when placed in the C3 Corvette chassis. Pre-1977 cars without the power-steering option can run their choice of oil pans including the standard F-body pan and pick-up tube. For power-steering equipped cars, the High Clearance Moroso oil pan kit allows for sufficient clearance of the power-steering control valve while still retaining an adequate oil capacity. That said, if your car is extremely low to the ground, you may be required to modify the pan to prevent it contacting the road or install an aftermarket power steering kit in order to use a different pan entirely.
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3. Exhaust System
With the engine securely placed in the chassis, the next step is deciding on which type of exhaust setup to run. With the BRP LS swap kit, you have the option of long tube ceramic coated headers in 1-3/4", 1-7/8", or 2" diameters. Similarly, they offer coated 1-3/4" or stainless 1-7/8" mid-length header options as well. If you are interested in going a different route than the swap kit options, companies like Custom Image Corvettes and Stainless Headers Mfg Inc offer some exotic side pipe headers in various materials and sizes made specific for third gen Corvettes equipped with LS engines.
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4. Wiring Harness
Sorting out the necessary wiring for a new engine can be torture, but rest assured that your swap kit will come with a complete wiring harness and computer to suit your LS powerplant. While just about any LS wiring harness from companies like Haltech or Painless will suffice, BRP's kit provides a bare-bones harness that is void of all the unnecessary items such as anti-theft and post-catalytic O2 sensors but provides heat resistant wrapping and labeled connectors for all the necessities. Also included is a waterproof fuse box that can be mounted virtually anywhere and an ECM that can be flashed to match the exact spec of your engine. If you a planning on putting an LS into your C3 Vette, simplify your life with one of these vehicle specific wiring kits.
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5. Radiator & Accessory Drive
When replacing your old engine with a new LS unit, it is wise to upgrade the radiator to bring the entire cooling system up to modern standards. There are a number of aftermarket aluminum replacement radiators from companies such as Champion, Dewitt's, and even BRP that will drop right into the stock location without any modifications. Furthermore, owners have the option of 2, 3, or 4 core units and optional electric cooling fans to keep engine temps at a minimum. Also, a nice feature of the LS engine swap kits is that the accessory drive bracket setup easily and conveniently allows all of the original accessories to mount to the front of the LS engine. Note that you will need an ignition coil relocation kit to prevent the rearmost coils from contacting the air-conditioning unit and brake booster.
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6. Fuel Tank & Fuel Pump
With the C3 Corvette using a carburetor and a mechanical fuel pump to control fueling to the engine, it is safe to say that the stock fuel system components are not cut out for a modern LS motor. Fortunately, the BRP Tank kit makes the conversion to EFI effortless. The kit contains a new baffled fuel tank designed specifically for the C3 Vette and includes provisions for the in-tank fuel pump and sending unit, wiring harness, and vent/supply/return ports. Depending on your choice of LS motor, several fuel pump options are available to meet the fueling needs of most high horsepower setups.
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For help keeping your LS powered car in fine tune, see the how to section of LS1Tech.com