Oversized valves and poorly made heads, also create an opportunity for the valve seats to melt and sink into the heads. This happened on 3 sets of heads before I found out that oversized valves, especially on heads made, where the exhaust ports are made at casting time with plugs, were the culprit. I then got a pair of genuine VW heads with normal size valves and this problem did not occur again.
See N64KR at <http://krbuilder.org/> http://KRBuilder.org - Then click on the pics 2015 KR Gathering - McMinnville, OR. September 3 - 6 -- See U There. Peoples Choice at 2013 - KR Gathering in Mt. Vernon, Il - MVN Best KR at 2013 - KR Gathering in Mt. Vernon, Il - MVN Best Interior at 2013 - KR Gathering in Mt. Vernon, Il - MVN Best Paint at 2013 - KR Gathering in Mt. Vernon, Il - MVN Best Firwwall Forward at 2013 - KR Gathering in Mt. Vernon, Il - MVN Best Interior and Panel at 2008 - KR Gathering in Mt. Vernon, Il - MVN Daniel R. Heath - Lexington, SC -----Original Message----- If I recall correctly, Great Plains says that they don't use oversize valves because it can/will cause cracking in the head between valves... and they don't use aluminum pushrods.
