designed to withstand 600°f specially formulated silicone developed to be compatible ... in a performance street racing engine application part no 5820 5821 5822 5812 ... use w/manifolds w/o upper bolt holes ford 65-67 289-302 exc factory hp 1/16 ... extra large square port 2.09 x 2.09 ford/mercury all 302 oval port 62-90 221- ... dohc round port chrysler/dodge/plymouth 67-74 273-318 stock port 1.34w x 1.82h 68-89 ... rubber material combination compensates for surface irregularities and resists high ... temperature incorporates steel carrier for stability and proper gasket alignment ... v8 283-400 1958-86 v8 396-454 1965-90 ford 289-351w 1965-95 part no 5853g 5854g ... rubber provides a positive sealing force created by controlled swell of the ... gasket when exposed to hot engine oil once swelling is achieved at a ...