<div class="bbWrapper">A major exhaust manifold leak is usually heard as a tick or snap which increaes with RPM and is loudest when the engine is cold. Remember 4 stroke engines, are suck, squeeze, bang, blow; and the parts on the "suck" side of things are prone to vacuum leaks - meaning the induction parts such as carb, intake manifold and somtimes PCV systems. I've never had a vacuum leak at a valve cover or exhaust manifold. As noted, if you have a power brake booster its worth checking that as well.<br />
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Also I've prob put two dozen Pertronix conversions in vintage cars, there was a spate of Meixo-built Flame Thrower coils that had intermittent failures, the latest ones seem to be fine, but if yours is an older one I'd replace it.</div>
