My photo shows a problem after 3-4 hours of use (multiple sessions). It was mounted on a Holley 4150 (4801-1 to be exact) and aluminum intake manifold (1971 Chevy Corvette C3 LT-1). Of course there were aramid pads (Victor Reinz) on both sides with heat capacities up to 300Β°C (572FΒ°).