Although the head gasket design is questionable and disimilar metals are used for the heads and block, increasing the air flow of the stock exhaust system will contribute significantly to their lifespan. This is due to the fact that an increase in air flow from the exhaust also allows heat to escape the cylinder chambers faster and releases combustion byproducts faster. Both of these things, heat and backpressure, are a significant contributor to head gasket failure. <A HREF="http://www.sccoa.com/articles/cwexhaust.html">here</A> is a technical reference. Many members and SC owners of the past have explored this issue, and have come to the conclusion that the catalytic converter and resonator are 2 of the largest culprits for backpressure in the stock exhaust system. being that the resonator is usually cheaper a&/or easier to change than a high flow catalytic converter, this is usually changed first. Now of course a regular maintainance schedule including oil, coolant, tuneup and lub changes always increases the cars lifespan and keeps it in better condition longer. Being that the metal in the top of this engine is disimilar from the block, regular coolant changes are especially beneficial. As are high octane gasoline and regular tuneups to prevent ping, or detonation. But in any case, exhaust upgrades go a long way to help the head gaskets.