Description 20V 4age- TRD head gasket Genuine Tokyo Technocraft product with a thickness of 0.8mm and a heavy duty 4-layer metal construction. Compression ratio change Due to being a thinner gasket than genuine this part raises the static compression ratio. Shown below is the change when used in the place of the original Toyota part. Figures are on the assumption of the engine being otherwise unmodified and the quotes figures being accurate. 20V Silvertop: From 10.5 to 11:1 20V Blacktop: From 11:1 to 11.5:1 Bore size compatibility These gaskets have a bore opening diameter of 82.6mm, this would suggest that they are compatible with up to a 1mm (82mm) piston size. Engine compatibility CAN NOT be used on a 16V 4AGE due to the different cooling system configuration. Note When this thinner gasket is fitted to an otherwise unmodified 20V Silvertop it remains a non-interference design.
