What You Need To Know About Engine Swaps

Engine Swapping Your Classic Car

Swapping the engine in your classic isn’t a new idea. People have been engine swapping since these cars were new! There are many reasons to swap but generally, people swap because they want something more powerful. That could mean going from a Small-Block to a Big-Block or swapping in a modern LS engine. 

No matter what engine you’re going from and going to, the process is more or less the same. If you’re going with a popular swap like a Small-Block, Big-Block, or even LS, we have everything you need to make it a bolt-in process. 

Engine Swap

Pulling your old engine is pretty straightforward – keep unbolting things until you can yank it out, right? More or less that’s the process, but it’s great to document where things are mounted, how they are mounted, and what bolts they are mounted with. In essence, you have to remove everything until the last thing is the motor mounts and you can pull it out. 

Let’s take a look at installing the new engine, which will help you with removing your old engine. We like to look at the engine and break it down by different systems. For example the exhaust system, cooling system, etc. We tackle them one at a time. 

Mounting The Engine

Let’s start with bolting the engine in first. This requires the proper motor mounts and frame horns. For the popular applications, we have these – but if you’re doing something crazy different then you might have to fabricate up something yourself. Also important to note that you have the correct oil pan on the engine as well. 

During the process of bolting in the engine,  you’ll need to bolt it to your transmission as well. You might be using a stock transmission or upgrading to something more modern, but either way, you’ll need it to bolt the engine too. 

With the engine firmly nestled into its new home, it’s time to start working on each system and checking them off the list. Let’s tackle the exhaust system first. 

Exhaust System

The reason to tackle the exhaust system first is that with headers, sometimes you have to undo a motor mount and tilt the engine to get the header in. This is a lot easier with nothing else in the way. Remember that lots of headers actually fit by sliding them up from the under the car and not sliding them down from the top. With the headers or manifolds secured, we can move on to the next system. 

Cooling System

We prefer to then work on the accessory drive system along with the cooling system as these two work together. If you’re swapping in a new engine then most likely your old accessory drive isn’t going to work unless you’re swapping the same type of engine, such as a Big-Block to a Big-Block. 

When working on the accessory drive it’s the perfect time to work on your radiator and cooling system. In some applications, you might be able to utilize the radiator that was in there, but in other cases, you’ll need to change it out or upgrade it. While you’re doing this you can look at your fan setup as well, whether it’s mechanical or electric. Remember too you’ll need new radiator hoses to go from the engine over to the radiator. 

Fuel System

The fuel system can be simple or complex. If going from one carbureted engine to another, you just need the fuel line coming from the tank and hook it up to the fuel pump. However, if you’re going up in power a significant amount, you might have to install a larger line to accommodate more fuel. 

If you’re upgrading to fuel injection, you’ll need a high-pressure fuel system with a bare minimum of 3/8″(-6AN) fuel feed. Then on the engine, you’ll need to plumb the fuel injection unit such as a Sniper or plumb the fuel rails if it’s multi-port. 

Hydraulic System

After the acessory drive is figured out and installed, next is the Power Steering system. While a smaller system, this still needs to be thought out and installed. In most applications the reservoir is attached to the pump and it’s as simple as hooking the lines up to the pump. Some applications the reservoir is remote which requires an additional line to supply the pump. 

Electrical System

Wiring up a new engine can be fairly easy or fairly complex depending on what type of engine you choose. If it’s something simple like a carbureted Small-Block, there are relatively few wires. A fuel-injected LS engine will require more wiring though. 

No matter what engine you’re installing, there are a few things that need to be handled properly. For starters, proper grounding. We suggest a heavy-duty battery cable going straight from the negative terminal on the battery to the engine block. And because you can never have too many grounds, we would run a battery cable from the block to the frame. The ground straps from the heads to the body. Most electrical issues are the result of poor grounds. 

While working on the electrical system it’s important to have proper charging as well. In stock applications, this is usually a charge wire that goes into the body harness. However, we’d always recommend a large gauge charge wire to go from the charging lug directly to the battery, or the starter if you have a trunk-mounted battery. 

If you’re changing to fuel injection, you’ll also need to add that wiring to the engine along with the computer. Again it’s crucial to have proper grounds or you’ll have all sorts of issues with the fuel injection system. 

Fluids And Final Touches

With all the different systems hooked up, it’s almost time to fire it up! Remember to make sure you add oil to the engine, fluid to the trans, the power steering reservoir, and water/antifreeze. We’ve heard stories of people getting ahead of themselves and firing up their new engines without any oil them! 

If you need any products for your engine swap or have any questions, hop on SS396.com or give our friendly techs a call at (203) 235-1200

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