FACES DIRECTLY FORWARD - 21MM ID AT THE CARB AND 16MM ID AT THE HEAD NOT FOR STOCK 42MM PATTERN CARBS ON THE 1982 AND 1983 PASSPORTS. BUT IS FOR ADDING 48MM BOLT PATTERN AFTERMARKET CARBS TO THEM THIS IS A STOCK MANIFOLD FOR NEW STYLE C90'S (NOT_FROM_USA) 318P @ *INTAKE_MANIFOLD TO_HEAD_ORING 27MM_X_2MM 91305-KF0-003 1/20M CT110_S90 (R2102) THIS IS THE O-RING FOR THE BASE OF THE MANIFOLD. IT GOES BETWEEN THE MANIFOLD AND THE HEAD. WITH THESES MANIFOLDS THERE IS NO GASKET JUST THE O-RING BETWEEN THE HEAD AND THE MANIFOLD. IT FITS THE (78 TO 82 CT70'S AND CT90'S), ALL CT110'S AND ALL PASSPORTS. R2102