Swapping an LS or LT engine into a classic or late-model GM platform has never been more popular… but for many enthusiasts, the process can feel overwhelming. Parts don’t always match, driveline angles get compromised, small fitment surprises snowball into major frustrations, and the language coming from the garage can get ‘spicy.’

The vibe is about to improve. Holley’s Engine Swap Essentials Kits answer these problems directly by giving builder/enthusiasts what they truly need: less complexity, failsafe fitment, and a clear upgrade path as their build progresses. Instead of feeling anxious, customers can approach their swap with confidence knowing Holley has verified every component on real vehicles—not just 3D models.

“We don’t want you to have to Google and mix and match and worry about what fits what,” said Jake Anderson, Product Manager, American Performance at Holley. “We’d rather be a turnkey solution. So if this is your first time doing an LS swap, we can kind of take a lot of the headache and the research part out for you.” That’s the part nobody mentions when the swap looks easy on paper.

Making sure parts are compatible, but also that driveline geometry and clearance are correct and verified. The story here is less about flashy new hardware and more about reducing wrong turns before the project ever gets sideways.

More Than a Bundle

“We did not organize these things well initially. It was very hard to figure out what you needed for your car. And sometimes some of the kits were incomplete. So we went through and tried to fill in the gaps and kind of logically put everything together where it’s now a turnkey solution,” said Anderson.

Most of the individual components already existed; the difference now is how Holley has reshaped and improved the kit’s execution. “We did go back through, and engineering verified everything,” said Mark Gearhart, Holley’s Director of American Performance. Ensuring customers receive all they need in a kit, including hardware and brackets. “We took the extra effort to make sure it’s as complete as possible.”

Shop the entire lineup of Holley LS/LT Swap Essentials Kits here.

That is exactly why this matters to actual builders. Plenty of companies sell you parts. What Holley is trying to do here is own more of the integration work upstream. Instead of asking the buyer to play systems engineer—mounts first, then pan fitment, then header clearance, then front-drive conflicts—the line is built as a verified-fitment ladder that follows the real sequence of a swap. That’s a lot more useful than a big pile of “compatible” parts that only become questionable after the engine is under the hood.

Who These Kits Are Really For

If you have ever done one of these swaps, you already know the domino effect. Engine position affects oil pan clearance. Oil pan choice affects crossmember and ground clearance. Mount location affects header routing. Header routing affects exhaust path. Accessory drive choice can open a whole different argument with the steering, radiator, hoses, and underhood real estate. All that skips over the driveline angle, which, if incorrect, can wreak havoc. These parts don’t live in separate worlds, even if they’re typically sold that way.

Holley clearly aims at a broad group of swappers. Kits are designed for plug-and-play usage, whether first-time swappers with a junkyard 5.3L and a G-Body or full-tilt shops with LTs in a first-generation Camaro. The pricing structure and layout make it easier to budget for your at-home build and for shops to quote more accurately. Plus, dealers receive similar margins on kits as they do with other Holley products.

That also explains the five-level structure. This is not a simple good-better-best pricing ladder; it follows the packaging logic of the swap rather than just stacking prices. “If you want to do a bare bones junkyard build and just get it rolling, we have you covered with an SE1 kit,” said Anderson. “Or if you want to do a really nice show car, we’ve got you covered with an SE5 kit.”

All level kits feature built-in discounts, which increase as the levels do. You can save over $500 depending on the combination.

LT/LS Swap Levels Explained

Each level includes the previous level’s kit, with added parts.

• Level 1 — Establishes the mount foundation, with only motor and transmission mounts. All available transmission adapters are included in their corresponding automatic or manual transmission kits to reduce complexity.
• Level 2 — Adds the oil pan that’s verified to fit in that particular chassis. LT kits are pan only, whereas LS kits include oil pan bolts, gasket, and dipstick tube.
• Level 3 — Adds headers or exhaust manifolds that are verified to fit that particular chassis. Kits offered with headers are all 304 stainless steel Hooker Blackheart brand with 1 7/8-inch primaries.
• Level 4 — Adds a Hooker Blackheart 304 stainless steel header-back exhaust system for that chassis.
• Level 5 — Adds the complete black powder coated accessory drive kit for that chassis. These kits include air conditioning, power steering, damper, and high amp one-wire alternator.

Level 1: Start With the Foundation

Level 1 includes the engine mounts and transmission crossmember, and its job is straightforward: put the engine and transmission in the right place in the chassis.

The mounts use heavy-duty 11-gauge steel with reinforcement ribs, a two-piece bolt-together design, black polyurethane inserts with molded steel locating tabs, and included hardware. The crossmembers are 3/16-inch steel and are designed around proper driveline angles with clearance for 3-inch exhaust. Transmission crossmembers will include brackets and hardware for all available transmissions to ensure everything you need is included.

“Level ones are the bare minimum you need to set the engine and transmission into your car,” said Anderson. That sounds simple, but it’s a big deal. Get the engine in the wrong place, and every decision after that gets uglier.

Shop Holley Level 1 LS/LT Swap Essentials Kits here.

Level 1 kits start between $690 and $780, depending on application, which makes them the entry point for budget-minded builders who already have a plan for the rest of the combo or want to build the package in stages.

Level 2: Oil Pan Fitment Stops Being a Guess

Level 2 adds one of the most chassis-sensitive parts in any swap: the oil pan. This is where the system starts feeling less like a mount kit and more like a packaging solution. The oil pan is matched to the chassis and mount package, which matters because pan clearance is one of the easiest ways to derail an otherwise solid swap plan.

Holley leans hard into OE-style design traits here: OE oil-filter mounting, OE oil-cooler provision, OE flange sealing, structural rigidity, OE bellhousing attachments, along with chassis clearance and optional upgraded racing baffles. That may sound like catalog language at first glance, but for the guy under the car, it translates into fewer surprises and greater confidence in fitment.

Shop Holley Level 2 LS/LT Swap Essentials Kits here.

Level 2 starts between $1,220 and $1,370 and for many builders, this is a very attractive stopping point. Once the mounts and pan are sorted, much of the foundational uncertainty goes away.

Level 3: Where the Real Swap Headaches Usually Start

Level 3 adds headers or exhaust manifolds confirmed to work with the mount and crossmember package. This is a big step because exhaust fitment is where a lot of LS/LT swaps stop being fun. Steering shafts, frame clearance, ground clearance, collector location, starter clearance—this is where “it should fit” and “it actually fits” stop being the same thing.

Depending on the application, Level 3 can include long-tube or mid-length headers, or cast-style manifolds. The stainless headers are mandrel-bent 304 stainless steel pieces designed for maximum ground clearance and built around a merged collector with an internal spike. Where manifolds are used, it’s a tight-tuck fit, a traditional muscle-car look, and high-silicon-moly ductile-iron construction for durability and corrosion resistance.

Shop Holley Level 3 LS/LT Swap Essentials Kits here.

Level 3 starts between $1,950 and $2,300, depending on the application.

Level 4: A More Complete Flow Path

Level 4 adds the header-back exhaust, turning the package into more of a full-car system. Complete exhaust systems feature mandrel-bent 304 stainless steel piping with a merged-X crossover and absorption mufflers, designed to balance performance with reduced drone. It’ll connect directly to Holley headers or manifolds while maintaining ground clearance and wide-tire compatibility.

That matters because once you get into the exhaust side of a swap, the difference between “I have headers” and “I have an actual exhaust plan” is a pretty big one.

Shop Holley Level 4 LS/LT Swap Essentials Kits here.

Level 4 moves the kit from solving front-half fitment to solving the whole path farther back in the vehicle. The starting price here is between $2,730 and $3,500, depending on the application.

Level 5: The Premium, Most Complete Version

Level 5 adds the accessory drive, and anybody who has chased front-drive packaging on a swap knows exactly why that matters. Steering clearance, hose routing, radiator placement, belt path, overall underhood cleanliness—accessory drives have a way of becoming their own compatibility rabbit hole if they are handled separately. Plus! Holley accessory drives greatly increase the under-hood look, styling, and tighter packaging.

The accessory-drive side of the program includes high-, mid-, or low-mount options depending on the chassis, along with bracketless-style mounting, bottom-outlet heater-hose options for clearance, a 150-amp LT1-style alternator, LT1-style water-pump cartridge design, and a Type II power-steering pump with baffled reservoir. This means that if you have an issue down the road, replacement parts are easy to find.

Anderson noted that the accessory drive itself may not be new hardware, but the value is that it is “confirmed to fit that particular chassis,” and that the higher kit levels bring stronger savings versus piecing everything together individually.

Shop Holley Level 5 LS/LT Swap Essentials Kits here.

Level 5 starts between $5,700 and $5,900, depending on the application. It is clearly the premium tier, and not every builder needs it. But for a cleaner, more complete package with fewer unanswered questions, it makes a lot of sense.

What “Verified Fitment” Actually Means

This is one phrase that deserves translation, because it can sound like vague marketing unless somebody explains it.

According to Mark, Holley is not using that label loosely. “We’re not going to mark anything that’s verified fitment unless we can confidently stand behind the fact that we have verified in one way or another… that that fitment works.” He added that verification can come through in-house work or trusted outside sources, but the core point is the same: Holley wants the combinations tied to real chassis validation, not just a hopeful compatibility chart.

Anderson described the same thing in simpler terms: “We went through and tried to make sure that everything plays nice together and that all the parts will fit the chassis and clear everything on those kits.” That is probably the best way to think about the line. Verified fitment here means the hard parts were chosen around how the engine actually sits in the vehicle, how the pan clears, how the exhaust routes, and how the package works as a system.

How Builders Should Shop the System

Along with the simplified part numbers and kits, so is the shopping experience. Holley is adding a configurator, which is just a fancy way of saying that once you pick your car and drivetrain, the rest is easy.

Start application-first, not part-first. Select the chassis. Confirm what levels are actually offered for that vehicle. Then decide how much of the swap you want Holley to solve for you in one shot. That sounds obvious, but it is really the backbone of the whole program.

Shop the entire lineup of Holley LS/LT Swap Essentials Kits here.

The one caution is simple: don’t assume every platform gets the full five-level menu. Coverage varies by application. Some chassis stop at Level 2, 3, or 4, while Holley continues expanding deeper coverage in key GM platforms.

Smart Part Numbers

Along with the simplification of kits comes better part numbers. “It’s a much better way of understanding rather than a string of numbers that doesn’t mean anything to the customer,” said Matt Bierbower, Director of Product Marketing at Holley.

Part Number Decoder:

SE1 / SE2 / SE3 / SE4 / SE5 = the kit level

Platform Code = the vehicle family/chassis

Engine Code = the engine family

Transmission Letter = Automatic or Manual

Example: SE1-GMG-LSXA

• SE1 = Swap Essentials Level 1

• GMG = GM G-body

• LSX = LS engine platform

• A = automatic transmission

In terms of transmission installation, transmission crossmembers may include extra brackets and hardware to better ensure everything you need is there, further simplifying the shopping process.

What’s Next?

Holley says the Swap Essentials line will expand beyond GM LS/LT applications, with Mopar and Ford kits planned during 2026. On the GM side, the company is also continuing to expand Level coverage across existing platforms, including broader C10 support. To see these kits in action check out the Swap Essentials video below.