88" to 95" big bore conversion. Used with stock heads and cylinders. By boring the stock cylinders from 3-3/4" to 3-7/8" big bore size engine capacity will increase from 88" to 95". High compression (pop-up). 10.5:1 CR. Piston weight 437gr. Piston pin weight 97gr. / Head type: Dome. Dome -11.2cc / Compression height 1.270". Bore 3.875" / Stroke 4.000". Rod length 7.667" / Cylinder length 4.938". Comes with T6 heat treated 390 Hypereutectic cast pistons with 16% silicone levels which enables running a very tight clearance for longevity and hardly any piston noise. Note: Top compression ring will need additional clearance. See instructions.