These 88mm pistons and cylinders are truly a great value and super simple to use. They will slip right inside the engine case of a stock VW engine without machining the case. The heads will need to be cut for 90.5/92mm size. They have even thicker walls than 90.5mm cylinders, making them extremely durable. You'll be able to upgrade your stock 1600cc to a 1679cc for more power without splitting the case, and not lose any reliability. Super nice, and at a great price. These are used by the top VW engine builders in the country! We're also to help with all your other engine building needs, carrying top quality components at great prices.