when the heads get milled,/block decked or even diff heads being used other than it had....or when intake is an aftermarket piece ...thing don't always line up super tight...which is a good reason for a thicker gasket, let alone it's a bi metal situation where when/if the copper coat or whatever gives to corrsion forming...it's will leak.
Mine ran good at 1st, then blew smoke out of the passenger exhaust bank cause it started sucking oil....let alone the tiny lil white veins on the dip stick=water in oil.
If you're determined to use them or ?...then better hang'em on a coat hanger and then spray the ever living sht out of them with the copper coat and let them dry....then when installing them use black rtv at the water passages still.
