Manufactured from 3mm combined wall thickness SUS321 stainless steel this manifold features mandrel bent large 42mm pipes for maximum flow and increased horsepower. Designed to suit RB20DET and RB25DET engines and turbos with a T3 inlet flange (high mount). Supplied with 2 bolt wastegate port to fit 35 and 38mm wastegates. Note: On the RB20 head, the water jackets line up a little different than the RB25. Same block, same head, same bolt pattern, however on the RB20 the port diameter is smaller than the RB25.