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On 13 Mar 2001, at 14:50, Dave Campen wrote: > I've noticed recently that a number of parts shops are selling new Mexican > heads with a long-reach small diameter spark plug, and smaller valve sizes. > These heads are definitely made for lead-free fuel and presumably should > resist cracking better as well. I suppose the small valves would make them > less suitable for a tuned engine, though. The space between the spark plug hole and the valve seat is the weak point on these heads; that's where they crack. Making this area thicker by going to a 3/4" SP thread should be a big help and is something that I've heard of several suppliers doing, but I've never seen one. If you also make the valves smaller that helps a lot also, but also cuts down on the engine's breathing. Considering that most of the sales for this kind of head are to the high performance crowd, this seems like a counterproductive way to go. Rather strange. - Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA ------------------------------------------------------------------- Search old messages on the Web! Visit http://www.vwtype3.org/list/