You can get factory feeder drums for P3 systems in 7", 8", and 8.625". I have installed a smaller rear feed drum in some P1's and I went with 7" instead of the factory 8". I had a machine shop make them for me and they used the same thickness as the old one. They used the single guide rings like original for the W-rings were not available when I had the last ones built. The numbers for W-ring kits can be found in the Gleaner service bullitons. Gleaner and loewen have shock kits for the R42,52,62,and72. I made up my own kits for early N's and R's. loewen now has the kits for R40,50 and is working on the kits for the other machines. I'll check with loewen tomorrow. Catch you later.