http://thebakeliteradio.com/sawspares.com/page10/page10.htmlfor my part, completed my 15th rebuild in as many years. I decided on the 310/039 to go back to the standard cylinder, it is not worth the trials and errors with the decompression ports. no point in writing a 2000 word essay here on my trials and tribulations. by golly I could draw all the parts by now, blindfolded.