[jonnyk]

I still can't believe this keeps popping up. The TFS valve guide problems were with the pedestal mount heads, which were LONG since rectified. However, with that being said, they are still one of the more sensitive heads to valvetrain geometry, and incorrect length pushrods will ruin a set of guides regardless of how "good" they are in a big hurry. You need approximately 1/2" longer pushrods than stock...which is usually either 6.700" or 6.750", depending on the engine. If you think you have a guide problem, won't a leakdown test help narrow it down for you?