Browse any car forum or automotive based social site and you'll come across people talking about engine swaps as if it's something you can do in a weekend. It's generally not, and definitely not for the amateur mechanic. It's a complicated proposition to put a modern engine into a modern car it wasn't designed for. Complicated also usually means expensive, and things that have to be taken into account include cutting and fabrication, wiring, electronic control units, mating the transmission or installing a new one. Then there are the cooling and fuel systems to consider and if you're adding a lot more power then you need to make sure the whole drivetrain can take it.

That said, engine swaps are not impossible. Particularly if you keep it as simple as possible. And at this point, there's a lot of documentation out there on swapping particular engines and particular cars. For the most common swaps, there are kits out there to buy with plans and pre-fabricated parts that will make life a lot easier. But what engine should you swap if you want the shortest distance to a big power increase? Well, these are the most common engines people like to use.

Toyota 2JZ

Toyota's 2JZ engines came in a few different flavors, but the factory turbocharged ones are the most popular. All of them are as close to bulletproof as an engine can get and need little strengthening to net real power gains from extra boost. The one everyone thinks of first is the 3.0-liter twin-turbo 2JZ-GTE. It's gotten expensive to find a solid running example, particularly with the factory GETRAG transmission. If you're not going for crazy horsepower, don't rule out the later de-stroked and single-turbocharged, 2.5L IJZ-GTE.

Retrofitting into a non-Toyota chassis is the big challenge, but there are several companies out there making installation kits or, if you have the cash, willing and able to build a turnkey solution.

General Motors LS Series

There's a reason the LS swap is so ubiquitous in America. The LS line of V8 engines started in 1997 and featured in many GM cars including the Camaro, Impala, Cadillac's CTS-V, and so much more. Books have been written on the subject of variations of LS engines but, briefly, the 5.7-liter LS1 is the oldest and most adaptable and the 7.0L LS7 and LSX are going to bring the most power and complication before you get to the 6.2-liter supercharged LS9 from the Corvette ZR1. The other option for those with cash to burn is a brand new specialty crate engine for instant big power.

Just about every car you can think of has been LS swapped at this point, but the problem issue is usually the extra weight, particularly with cast iron-block engines. Then, there's the usually huge addition of torque to the drivetrain that has to be accounted for. The big advantage comes with tuning and the aftermarket. There's not much that hasn't already been done with an LS, from generating a modest power boost to building viscous drag strip rippers of an engine.

Rover V8

Outside of America, the Rover V8 comes close in its availability and tune-ability, and its DNA goes back to the Buick 250 engine from the 1950s. In the form we know and love though, the Rover V8 was first used in 1967 and stayed in production in a large variety of cars until 2006. We mostly know it for being in Land Rover and Range Rover models, but it's been used in a variety of European production cars over the decades. The Rover V8 is still a favorite for engine swaps and kit cars due to its lightweight aluminum design.

Like LS engines, the Rover V8 has been swapped into just about everything with rear-wheel drive, has a large aftermarket, and is well documented for tuning. The car below is a Ford Capri with a 3.5-liter Rover V8 installed.

Honda V-TEC B-Series

Even now, 15 years after Honda stopped producing B-Series engines it appears in some of the most powerful Honda's you'll see. The aftermarket is strong and the engines are tunable, although you'll be spending a pretty penny to get into the 350+ horsepower range. However, the engines aren't expensive to buy along with the hardware you'll need to perform a swap into a Honda or Integra model. Reliability is also a key word when using Honda engines for a swap.

Nissan SR20DET

Nissan's turbocharged 4-cylinder is a favorite for drifters in the beginner to mid-level of the field. The SR20DET is a well proven platform for tuning and can be made to work transverse and longitudinal form, which increases the platforms it can be made to work on. Unfortunately, it has been out of production for a long time and the popularity of the SR20DET means its getting rare. It's not the easiest of swaps into a non-native chassis, but there are kits out there to help if you look.

Nissan RB26DETT

Nissan's almighty GT-R engine is not a swap for the faint hearted or someone on a shoestring budget. There's no other chassis it'll drop into easily and it's a straight-6 to make things even more awkward. On top of that, you'll need the rear-wheel-drive transmission that's usually sourced from Skylines using the RB25DETT engine unless you're prepared for an engineering nightmare. Of course, you could swap the RB25DETT into the project if you don't mind one less turbo.

The benefit of spending the money and dealing with the many headaches associated with swapping in an RB26DETT is a lot of power from a remarkably strong engine. Like the 2JZ, it doesn't require a lot in the way of stronger internals until you get truly serious about extra power on top of what you get just by swapping out the old engine. However, maintenance and modification can get expensive quickly.

What you're looking at in the pictures below is an insane swap. A 1994 Nissan Pulsar built for autocross and includes the Nissan Skyline R32 all-wheel-drive system.

Honda K-Series

The only Honda engine to outshine the B-Series in the aftermarket is the K-Series. They were common through the 2000s in performance models such as the Acura RSX Type-S, Honda Civic Si, and European Type R models. For a direct swap for anything with four cylinders, there's not much better that's naturally aspirated. On the flip side, they aren't cheap and once you start rolling in the cost of aftermarket components to deal with the shifter layout and engine orientation, things can get expensive. Although the owner of the RX-7 below must have thought it was easier to swap in a turbo K20 engine than deal with the existing rotary to make 435 horsepower on E85 fuel.

Mazda 13B

Mazda's legendary rotary is getting harder to find, and the one everybody wants is the twin-turbocharged 13B-REW from the third-generation RX-7. The single-turbo 13B-DEI can be found in the second-generation RX-7, but when you find and pay for one it's not going to be cheap or easy to swap. The aftermarket is slim and the rotary engine is a learning curve that takes dedicated care to maintain. However, if you put one in a Mazda MX-5 you become an instant internet hero and all the Instagram followers will be yours.

The swap below was finished by Grassroots Motor Sports after the project starter and GRM forum member Mike Smith passed away from cancer. It was auctioned off and the proceeds went to Smith's daughter's college fund.

Ford Ecoboost V6

For people that want the torque of a V8 but in a lighter and smaller package then Ford's Ecoboost V6 is a solid option that's gaining fast in popularity. 365 horsepower and 350 lb-ft of torque is the most common power output from the first generation and comes in single or twin-turbo flavor depending on where it comes from. The aftermarket is getting bigger and bigger and solid running examples are plentiful, but expect to have to do a lot of work with plumbing and wiring. However, if you're looking to restomod a classic Ford it should probably be the first option to research.

Honda J-Series

When it comes to bang for your buck for upgrading an old Honda or doing something a shade easier than a V8 swap into an MX-5, the V6 J-Series has you covered. There's not much in the way of aftermarket support but, depending on the model it's sourced from, it's an instant 240-310 horsepower and way more torque than your existing four-cylinder engine. The cheapest way to get 240 hardwearing horsepower is to raid an old Odyssey. Although aftermarket is scarce, there are some good kit solutions to help get one into an older Civic, Accord, CRX, or Integra. Or, of course, an MX-5.

Ford 5.0 V8

Before the LS became the default V8 swap, Ford's 5.0-liter HO V8 was the quickest and cheapest way to get a big bump in power. Today, it's 225 horsepower and 300 lb-ft of torque seems anemic, but the 5.0 responds well to a wide array of modifications, particularly when it comes to intake and exhaust. Parts cars are cheap to buy and bring the benefit of having all the sensors and wiring and other parts you'll need. The aftermarket is still big due to classic car enthusiasts and drag racers. Unfortunately, the 5.0 is heavy and a problem if keeping the balance of the car's chassis is important. However, putting one in an E30 BMW is an awesome way of confusing car enthusiasts as you drive by.