1275 + 60 oversize A series Classic Mini Piston Set High Compression 10.3/1 As fitted to late Rover Mini Cooper engines. Slipper type piston. High quality high silicon content pistons supplied with gudgeon pins and top quality Grant piston rings made in the USA 1.5mm, 1.5mm, 4mm. Very strong pistons that will take a lot of abuse. 8cc piston dish. These are the pistons to use in a high performance road engine. 1.5276” pin to crown height.