Most people don't understand head gasket technology. Unfortunately, some gasket kits that sell with performance rebuilds only have a common passenger head gasket included... for cost reasons only.

The Fel-Pro Performance head gaskets (SB example FP 1008) are truly intended for high-performance duties. Their primary design features a solid steel core, covered by thin fiber facings along with anti-stick coating and the fire ring is a SS armor wrapped around an inside pre-compressed wire ring --- very similar to diesel designs (high cylinder and compression ratios). For many years, these same gaskets have been the standard in sealing hi-performance race motors.... NASCAR and others exclusively used them.

A common passenger head gasket (SB example FP 8553) will not have SS armors, nor will it have the internal wire ring... and those are commonly sold in rebuilding kits. Install them on a hi-perf engine -- which WILL eventually be subjected detonation and/or pre-ignition -- and the common tin-plate cylinder armor will possibly fatigue and fail. This type of gasket is OK for common non-hi-performance engines.

Another concern is that yesteryear's gas had higher octane ratings vs today's gas. Older hi-compression ratio engines suffer from detonation and/or pre-ignition due to the reduced grades of common gasoling at then local stations.

Then, we have the new MLS head gaskets -- multi-layer-steel... most all top name brand gasket companies produce these .. for specific applications. These gaskets are superior in combustion sealing, however, their origin was to allow casting and bore distortions to become minimal -- a science! They require very smooth surface finishes (heads and deck) which some machine shops are not capable - or resistant -- to perform. Also, these head gasket are very expensive. For most older and traditional engines, this design is overkill, and may not even be offered.

I'm a former gasket applications engineer with a major company. There is a lot of marketing within the industry. Beware of what you buy... and you pay for what you get.