The RaggDoll Motorsports Inconel Head Bolt Kit is a high-strength engine hardware upgrade for the Porsche 718 Cayman & Boxster, engineered to maintain proper cylinder head clamping under extreme boost, heat, and cylinder pressure. Designed for high-performance, high-boost, and built-engine applications, this kit replaces the factory head bolts with aerospace-grade Inconel fasteners for maximum reliability.
This is a critical supporting upgrade for serious Porsche 718 engine builds.
The factory Porsche 718 head bolts are sufficient for stock power levels, but they become a limiting factor as boost pressure, combustion pressure, and operating temperatures increase. Under high load, OEM bolts can stretch, lose clamping force, or allow head lift—leading to gasket failure or engine damage.
The RaggDoll Motorsports Inconel Head Bolt Kit was developed to eliminate this weak point by providing significantly higher tensile strength, superior heat resistance, and improved clamping stability. This ensures the cylinder head remains securely sealed even in extreme operating conditions.
High cylinder pressures place extreme stress on the head-to-block interface. Inconel fasteners resist stretching and fatigue far better than standard steel bolts, helping maintain consistent clamping force and protecting head gasket sealing surfaces.
Inconel alloys are commonly used in aerospace and motorsports due to their ability to retain strength at high temperatures. This makes them ideal for turbocharged Porsche 718 engines operating under sustained boost and track conditions.
Ideal for Porsche 718 Cayman & Boxster owners building:
This upgrade is recommended whenever the engine is opened for internal work or when pushing beyond factory power limits.
Professional engine assembly is required.
Installation involves cylinder head removal and proper torque sequencing.
This kit should be installed in conjunction with:
Always consult with RaggDoll Motorsports prior to installation to confirm build compatibility and power goals.
RaggDoll Motorsports develops performance solutions for the Porsche 718 platform with a focus on reliability at elevated power levels. We understand that engine strength is only as good as its weakest component—and fasteners matter.
Stronger clamping.
Higher reliability.
Built to handle boost.
Built differently — because performance demands it.
Liza & most of the time Vince is amazing...lol. Nah, kidding, these guys are awesome folks to deal with. I purchased their Stage 2 turbo, turbo inlet, intercooler, engine tune, and high pressure fuel pump for my 2018 2.5L Boxster GTS and they're products and service have been top notch throughout the entire process.
Raggdoll Motorsports set up two dyno sessions for my Porsche Turbo S. The Porsche touts a 4.0-liter built engine and head work facilitated by Sam at ByDesign. Also has the XR ByDesign turbo kit with all the supporting mods. The first session the PDK kept transitioning out of manual mode. During the second session a boost leak at the throttle body boot ended the session early. We managed 812 hp on a Mustang dyno at only 20 psi of boost.
The people behind RaggDoll Motorsports have been in the game for a very long time and really know their stuff. They have a passion for modifying cars and are enthusiasts before anything else.
I purchased a RENNEN turbocharger for my 718 T. I had a special request, which was to get the turbine housing coated with Swain Tech white lightning thermal barrier coating and RaggDoll accommodated without hesitation even though it was something new for their team.
Hey All! Shout out to Liza and @Raggdolls718. Amazing customer service, product knowledge and a top quality product. Liza went out her way to accommodate my tight timeframe and the level communication and level of detail shared was amazing.
I purchased the Raggdoll Series One turbocharger upgrade and the turbo inlet upgrade from RMS for my Porsche 718 Cayman GTS and was very pleased with both the products and the customer service from RMS!
Engineered for the 718 platform, trusted worldwide. RaggDoll delivers high-performance parts, custom turbo innovations, and expert-level support for Porsche 718 drivers and tuners—from Las Vegas to Germany, Hong Kong, and beyond.
