LS Swapping a C3 Corvette (photos)
The C3 Corvette started strong in 1968 with powerful big and small block motors, but emissions choked the power out of them and many could use an engine transplant. Here's everything you need to shoehorn an LS engine in your C3 Corvette.
1. Headers and Exhaust
Swapping a modern LS motor in your classic C3 Corvette is a pretty simple process these days thanks to companies like BRP Hot Rods. BRP offers all the parts you need to complete the swap in one convenient place, all designed to fit your car with no extra cutting or fabrication work needed.
When it comes to headers, you've got two different options to choose from. Muscle Rod Headers are long tube units with 3/8" flanges. Offered in 1 3/4", 1 7/8", and 2" diameters, the Muscle Rods offer a variety of options to fit your high horsepower ride. Mid-length headers offer a tighter fit that looks great in a 1 7/8" diameter.
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2. Engine and Transmission Mounts and Adaptors
To mate your LS motor/tranny to your C3 chassis, there are lots of places to get complete engine and transmission mount kits. The kits comes with motor mounts, a transmission crossmember adapter, transmission mount, and all the required hardware. The LS motor will bolt up to old style automatic transmission, but you will need a special flexplate and a crank extender to center it (or just the extender and elongate the holes in the stock flex plate). Most people with manual transmission cars prefer to update, and two different modern 1manual transmission mount adapters are available. These enable you to use either the modern T-56 or TR-6060 transmissions, including those from the ZL1 Camaro or Cadillac CTS-V.
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3. Oil Pan and Oil Pump
In General you have two different oil pan options for your LS swap. The Moroso high clearance oil pan provides the clearance necessary to retain factory style power steering. If your car sits low to the ground and runs an aftermarket steering setup, you can opt for the factory F-Body oil pan that gives you more ground clearance. In addition, you may need an oil pump pickup tube girdle that is stronger than the GM single bolt mating flange.
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4. Wiring Harnesses and Coil Relocation Kit
Dealing with wiring can be a huge pain when installing a modern engine into an older car, but there are now many kits that make the process a snap. Most wiring harnesses comes 100% ready to go, and you can even get a reflashed OE computer for a true plug-and-play installation. One thing you will need in a C3 is a coil relocation kit, to prevent the rear coils from making contact with the power brake booster and air conditioning.
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5. Radiator and Accessory Drive
To keep your new LS motor cool, it isn't a bad idea to add an all-aluminum radiator, which is not hard to find to fit any C3 Corvette. These radiators are available in either black or bare aluminum, and you can opt for high performance electric fans if so desired. To make sure all of your accessories fit and look great, BRP and others offer all the parts and brackets you need in a variety of finishes.
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6. Fuel Tank, Pump, and Lines
A stock C3 fuel system won't cut it with an LS, which needs a steady flow of fuel to perform, and a return line for the EFI pump. Luckily for you, you can get replacement Corvette fuel tanks that fit like a glove, have provisions for the return line, and the ones from BRP even feature a baffling system designed to prevent fuel slosh during spirited driving. You'll need a fuel pump sized for the amount of power you plan on making, and it isn't a bad idea to replace all the old fuel line too, while you are at it.
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Ford help keeping your late model Vette running right check out the how to section of CorvetteForum.com