LQ9Motivation

So short version, have an LQ9 swapped into an 02 Silverado. Ran truck hard for 2 years, no problems. Planetary gear in the transmission eventually gave out. I'm thinking it just wound up to such a high RPM range it mushed a valve. Had transmission rebuilt and once valve gave way I had Bill & Jeff Ford out of Sylvania, Ga take a matching OEM head and put it on the flow bench to match.

Here I am about 5,000 miles later with another dropped valve. Waiting on a call back from Texas Speed about exact lift on the cam. Im thinking about 0.606. Which requires some milling for clearance on the valve spring seat. Could this be why I dropped another valve?? Not enough clearance would make sense, but I'm wondering if they did it to match why it didn't last near as long before it occurred for a second time.

Considering a set of Trickflow Specialty heads with a little machining to fit and compensate for the lift on the cam, but can anyone shed any kind of light on what else I could be running into? I'm open to all theories...



Just looking for help..

psicko

You can go over .650" without any special machining on the head. If you really want help, try to list the specifics of the engine, like what cam, springs, heads, etc.