No matter how much of an old-school purist you are, you can't deny that contemporary engines offer a multitude of benefits compared to the stock engines found in classic muscle cars. The most important difference is that American muscle cars from the 1960s and 1970s all rolled out of the factory with carbureted engines. Modern fuel-injected engines with electronic control units are much more fuel efficient and they produce far less emissions.
More importantly to driving enthusiasts, modern engines with electronic fuel injection systems are much easier to tune when modified. That means you'll have an easier time making horsepower gains while keeping your engine running smoothly. The only caveat is that you'll need a long list of supporting modifications to properly install a contemporary engine into a classic car.
Two Options: Swap Kits Versus Custom Fabrication
When you're coming up with your engine swap budget, you have to keep in mind all of the custom parts you'll need in order to fit your new engine into your old-school ride. Luckily, a myriad of enthusiasts have already swapped most of the popular modern V8 engines from General Motors, Ford, and Dodge into their classic rides. That means there are numerous aftermarket swap kits available for a lot of the popular platforms.
Aftermarket swap kits are designed to fit specific modern engines into specific classic car chassis. However, if you're dealing with a less popular chassis or an unconventional engine swap, you'll have to go the custom route. Metal fabrication companies, such as Suburban Welding & Steel LLC, can manufacture all of the same components you would get from a complete aftermarket kit, except the components will be carefully designed to fit your unique application. Even if there are aftermarket kits available for your engine swap, you should consider contacting a custom metal fabricator for a price quote to see if they can provide you with all of the parts you need for cheaper than the price of a pre-designed aftermarket kit.
To even fit your new engine into your classic car's engine bay, you'll need some custom exhaust headers. Your new engine will likely have drastically different external dimensions than your car's stock engine, so custom headers are required to clear the shock towers and other boundaries of the engine bay.
If you plan on keeping your new engine's air conditioning and power steering systems, your best bet is to go with a set of custom fabricated headers. That way, the fabrication company can design the header piping to clear your specific engine's air conditioning and steering components so you don't run into clearance issues.
Once you have a set of custom headers to fit your new engine into your engine bay, you need some custom motor mounts to bolt it onto the chassis. Depending on your platform, you may be able to find a set of aftermarket motor mounts that relocate the motor mount bolts so you can use your car's stock mounting location. In other cases, you'll need to have a fabrication company create new mounting points in your car's chassis along with custom mounting plates.
Drivetrain Mounts and Adapters
In addition to motor mounts, you'll need custom mounts to bolt your new transmission and other drivetrain components to the chassis. In some cases, you may even have to have the transmission tunnel on your car expanded or otherwise modified to clear the dimensions of your new transmission.
Once you have your engine, transmission, and rear end bolted up, you may find that the driveshaft and other drivetrain components are an improper length. After all, your new engine was designed for a modern car with a completely different wheelbase, so it's not unlikely that the drivetrain will perfectly line up with your classic car's chassis. If that's the case, you'll also need a custom driveshaft and custom mounting plates to properly get everything lined up.
Swapping a contemporary engine into a classic muscle car is a lot of work. Nevertheless, if you're a driving enthusiast, there's nothing like having the charm of a classic car with the performance of a modern drivetrain.