Big bore 103.6mm 996/997.1TT piston-cylinder set What is a Big bore 103.6mm 996/997.1TT piston-cylinder set? Using the highest quality Nikasil Coated Capricorn steel liners we could find, we’ve achieved durability and reliability rivaling the oem’s while also increasing the power and torque of your project substantially. CP pistons using 2618 alloys and DLC coated wrist pins are also run with this setup. Gt3 valve pockets and a perfect range of compression ratio depending on stroke can make these simply amazing on the street or track. The liners are available with reliefs for up to 12mm or 1/2″ head studs For milder builds, we have plain top flanges. For ultimate builds the top flanges are o-ringed for copper reciever grooves to match up to stainless steel rings in the heads. How big will my engine be with these? With stock 76.4 stroke, these are 3.9L. Throw our 80.4 crank in with these for an amazing 4.1L!  That’s a full 500cc greater than the stock 3.6L engine! We do have 82.4 cranks for the ultimate 4.2L builds as well! These definitely fit the “no replacement for displacement” saying. What do they fit? 2001-2005 Porsche 996 Turbo 2001-2005 Porsche 996 GT2 2001-2005 Porsche 996 X50 2007-2009 Porsche 997.1 Turbo 2007-2009 Porsche 997.1 GT2 2011-2012 Porsche GT2 RS 1999-2012 Porsche GT3 for Turbo conversions What else will I need with these? For the larger bore and large head studs we have Cometic Head gaskets to fit perfectly. For the base of the liners you’ll be needing some Cometic Base Gaskets to fit the 109mm spigots. Your engine case spigots and base of the liners will need to be machined to fit the larger spigot for the highest strength. Where can I learn more? Check out Protomotive’s YouTube Channel for great information and some fun too! Have us add our Big bore 103.6mm 996/997.1TT piston-cylinder set to your project, or grab some outright for your own project.