Builders are quietly scooping up a few different sleeper shells as the LS-swap market continues heating up. There are a few donor shells, in particular, that are being secretly hunted by collectors who are ahead of the curve. You don’t want to get left behind if you’re trying to work on a classic project that can handle plenty of V8 torque.These muscle cars span model years 1967 to 1992, offering a wide range of unique options for racing builds. They offer diverse benefits such as superior weight distribution, plenty of engine bay space, and affordability. Once word gets out, prices could quickly increase as the rarity of these models accelerates.Best of all, most of these muscle car shells have tons of aftermarket support. That means parts are available and easy to find. Plus, there are documented guides and experts to provide advice and assistance with every step of the way. The most difficult part of the process may involve trying to decide which shell to buy first. G-Body Monte Carlo SS Production Years: 1981 - 1988 Value: $2,500 - $6,000 Mecum AuctionsThe G-Body Monte Carlo SS is another hot rear-wheel-drive option with attractive aerodynamic styling. It has a lightweight chassis that provides a versatile platform for diverse projects. An LS swap replaces the 1980s 305 small block with a modern, reliable engine that instantly doubles the horsepower.Not only is the G-Body platform affordable, but it’s also very popular. There is a ton of after-market support as companies offer dedicated swap kits, including mounts and oil pans, to make dropping an LS into the spacious engine bay relatively easy. You can also reference numerous guides and helpful videos.The factory gauges are seamlessly integrated to read from the new engine computer, and parts such as the swap mounts and accessory drives are readily available. Plus, modern transmissions fit in the chassis for highway-friendly driving that the original three-speed transmission lacks. But be sure to plan for the right transmission and rear-end components to safely and reliably handle more torque. Mazda RX-7 FC Production Years: 1985 - 1992 Value: $3,000 - $10,000 Bring a TrailerThe second-generation Mazda RX-7 FC shell is an extremely popular option for an LS swap. Its superior rear-wheel-drive platform pairs with excellent handling dynamics to create an incredibly capable street or track car that easily handles massive low-end torque. This car weighs only 2,600 lbs. Many believe that it can out handle a Camaro.The aluminum LS block is also light, so the front-to-rear weight distribution ratio is well-balanced. Swapping the original rotary engine for an LS increases reliability and bypasses painful maintenance hurdles. It also delivers instant linear torque while rotary engines need high RPMs.The RX-7 FC benefits from being a popular conversion for decades. So there are plenty of durable off-the-shelf parts available with aftermarket support. But some Mazda purists believe that removing the Wankel engine is a crime and that may impact resale value later, with the potential to face criticism. Datsun 280ZX 2+2 Production Years: 1979 - 1983 Value: $7,000 - $12,000 MecumGenerally, the Datsun 240Z is the preferred muscle car for a lightweight track build. It weighs 2,300 lbs, while the Datsun 280ZX 2+2 weighs between 2,700 and 2,900 lbs. But the 280Z 2+2 has a stronger factory chassis, and it’s more rigid to provide enhanced crash protection. Also, it has a longer wheelbase for superior stability that better plants the rear tires.Heavier-duty parts such as the larger 13-inch clutch on manual models make the car easier to adapt to the increased low-end torque of LS engines. Plus, the Datsun 280ZX 2+2 features a standard, incredibly durable R200 differential and stronger axles, while the earlier 240Z models have a weaker R180 differential and smaller stub axles.The S130 (280ZX) has an incredibly spacious engine bay, meaning it can fit a pushrod V8 without requiring heavy cutting or modification of the firewall, and it has standard electronic fuel injection. This simplifies integrating the electrical and fuel delivery requirements. So the 280ZX 2+2 is much better prepared for reliably handling LS power. Also, LS swaps can impact the value of the 240Z for purists. Fox-Body Mustang LX 5.0 Production Years: 1987 - 1993 Value: $8,000 - $15,000MECUMWhile the base or four-cylinder Fox-Body Mustang is a more affordable starting point for an LS swap, it comes with a little more work. For example, it requires a complete overhaul of the fuel lines, wiring, and rear axle. The base shell has a weaker 7.5-inch rear end instead of the beefier factory 8.8-inch rear end.The Fox-Body LX 5.0 features a more durable suspension and heavier-duty brakes to handle immense LS power right out of the box. Plus, it has lighter weight than the GT trim, which is bogged down by bulky plastic cladding, for an enhanced power-to-weight ratio. Also, the LX 5.0 pairs an aerodynamic chassis with a spacious engine bay.MecumAlso, the aluminum-block LS is a pushrod engine with a surprisingly compact and convenient size. It can easily fit in the Fox-Body engine bay. It's smaller and lighter than modern Ford overhead cam engines like the Coyote, and requires fewer modifications to the firewall and body. The LS engine has superior engine management as well.The Fox-Body and LS platforms are both incredibly popular for hot rodders. This means that there is a ton of aftermarket support for off-the-shelf components, and it's easy to source parts such as K-members, headers, and motor mounts. But using a Chevy engine may upset Ford purists and impact the resale value later. First-Generation Chevrolet Camaro Production Years: 1967 - 1969 Value: $10,000 - $25,000 MecumThis is a classic rear-wheel-drive muscle car that was built to battle the Ford Mustang. For Chevy purists, the F-body platform handles LS power while maintaining a classic Chevy muscle car style and its iconic engine roar. It’s also incredibly popular among builders, so there is a ton of aftermarket support available.First-generation Chevy Camaro features such as its bolted on front subframe and spacious engine bay make it easy to combine the classic style with a more modern and reliable performance. Aftermarket alternatives accommodate an LS engine and suspension upgrades without having to modify the original chassis, which is another benefit for Chevrolet purists.Companies offer bolt-in swap kits that include everything you need, from headers and accessory drives to engine plates. Also, LS engines are lighter by 40 lbs compared to the old cast-iron small block. This greatly improves the front-to-rear weight distribution for superior handling. Plus, LS swaps provide turn-key reliability and the improved fuel efficiency of electronic fuel injectors. They can be paired with modern transmissions for improved highway driving.Source: Hagerty, Bring A Trailer