88" (3-3/4") to 95" (3-7/8") big bore conversion forged piston set. 9.25:1 CR with 85cc head. Piston weight 350gr. Piston pin weight 89gr. Piston pin dia. .927" / offset. Head type: Dome with -6.7cc. Compression height 1.263". Bore 3.875". Stroke 4.000". Rod length 7.667". Cyl. length 4.938". All KB forged pistons are made from 4032 alloy; a 11% silicon alloy that is formed in a forging press. Forging aluminum gives a superior strength and structural integrity on a molecular level; after which it is fully machined. The combination of this alloy and the forging process allows the piston to flex under detonation; or pre-ignition; giving the best resistance to cracking. Although 4032 has a low expansion rate; it is higher than the cast Hypereutectic. Therefore forged KB pistons will require about .001" wider piston to wall clearance. Pistons are sold as sets; complete with wrist pin retaining rings; wrist pins and piston rings. Note: All KB forged pistons come equipped with offset wrist pins / piston pins. There is a front and rear section on the piston and it is necessary to install it in the correct way. Please refer to the installation instructions; as provided with each piston set; prior to installation.