[Rev]

One of the advantages of TFTW heads is that the valve cover rim on the heads is raised about 1/4" so that you can run roller rockers with the stock valve covers.

Also I seem to remember a lengthy area of the installation instructions detailing how to check for correct push rod length so that the roller will end up in the middle of the valve stem after installation. That's very important to minimize side loading of the valve stem against the valve guides.

Rev