Trundles Cylinder Head Coolant Bypass to suit Nissan TD42 Engines Includes:1x Cylinder Head Coolant Bypass1x Fitting (or with line) - Please use Drop Down Menu to select desired fitting.1x Thermostat Housing (If Selected) - Please use Drop Down Menu to select whether you would like with or without Details- Designed to help reduce the micro boiling points in the TD42 Pre Combustion chamber areas in head- The genuine head fitting suits OEM heads with 34.9mm frost plug- The aftermarket head fitting suits heads with 36mm frost plug Optional Extras:- Billet adapter fitting by itself is $125- The full kit includes genuine Speedflow fittings and line assembled for $290.- We can also supply with a brand new genuine thermostat housing pre-drilled to suit. for an extra $85 Note: You will need to tap a M6 hole in the back of your head and a 1/4" NPT in your thermostat housing.