INSIDE DIMENSIONS 14.500 INS. X 10.500 INS; TOP 9 INS. W; 2.750 INS. FLANGE ON ALL SIDES WITH 20 HOLES 3/8 IN. IN DIA EVENLY SPACED; TOP VENT CONNECTION 3/4 IN. HOLE; 1 EA 2.500 IN. HOLE ON EACH SIDE FOR ENGINE COLLING CONNECTION; 1/3 IN. DIA HOLE FORWARD SIDE FIRE PUMPING CONNECTION