Changing push rod length won't move the wear pattern on our cars. Plus your pattern isn't anywhere near close to the edge of the valvestem.
It looks a little wide so I doubt you're right at correct mid-lift geometry, but it's a pain in the butt to move shaft heights and/or tip heights coupled with pushrod lengths and get it "perfect". And it would be patent infringement if the T&D's were built with correct geometry. unfortunately. (I've never owned a set so I have no idea how close they are to being right).
To answer your original question yes, you need longer pushrods when running alum heads. The thermal expansion rate of aluminum is right at double that of cast iron. When the engine is at operating temp the rocker shafts will have moved close to twice as far away from the cam shaft.
It looks a little wide so I doubt you're right at correct mid-lift geometry, but it's a pain in the butt to move shaft heights and/or tip heights coupled with pushrod lengths and get it "perfect". And it would be patent infringement if the T&D's were built with correct geometry. unfortunately. (I've never owned a set so I have no idea how close they are to being right).
To answer your original question yes, you need longer pushrods when running alum heads. The thermal expansion rate of aluminum is right at double that of cast iron. When the engine is at operating temp the rocker shafts will have moved close to twice as far away from the cam shaft.
