This Exhaust Manifold (header) makes a 120° bend for routing / exhaust outside the cowling or fuselage on a radio controlled airplane. / / This header is designed to fit the O.S. FS70 & FS91 Surpass series engines. / / INCLUDES: One 120° chromed exhaust manifold / (Has male threaded portion on one end & female threads on the other) / One hex nut / SPECS: Male End / Thread Pitch -0.75mm / Outside Diameter-0.425"(10.8mm) / Inside Diameter-0.320"(8.1mm ) / / Female End (exhaust connection) / Thread Pitch -0.75mm / Outside Diameter-0.509"(12.9mm) / Inside Diameter-0.408"(10.3mm) / === / Inside Exhaust Pipe Connector / Outside Diameter-0.509"(10.3mm) / Inside Diameter-0.409"(10.3mm) / Thread Depth -0.424"(10.7mm) / / jct4/7/00