BOLT PATTERN IS 45MM,,, CENTER HOLE IS 22MM,,, THICKNESS IS ABOUT 3MM. REQUIRES 2 OF OUR 31B FOR USE BETWEEN HEAD AND MANIFOLD CARB INSULATOR : GOES BETWEEN MANIFOLD AND HEAD THIS FITS HEADS FROM 50'S 70'S AND TRX90'S CENTER HOLE IS 22MM THICKNESS IS 3MM BOLT SPACING IS 39MM INSIDE TO INSIDE BOLT SPACING IS 51MM OUTSIDE TO OUTSIDE HEIGHT IS 38MM @ *GASKET INTAKE_TO_HEAD CT70KO_to_1977 ALL_SL/XL70'S (all_CT110's) (CT200?)7/20M (31B) THIS GOES CLOSEST TO THE HEAD ON THE INTAKE SIDE. FITS KO THRU 1977. and all atc70's 22MM CENTER 44MM BOLT PATTERN ALL HOLES ARE CENTERED all SL AND XL70'S TAKE 2 ONE ON BOTH SIDES OF THE INSOLATER 31B