Jay: I didn't see you said anything about helicals. We install green stem kit which adds a row of helicals on thresher side and it hooks up thresher helicals to separator helicals in three spots. We also shim every helical away from cage by 1_4 inch. We are also installing bean helical kit in some and leaving in for all crops. We have even installed 68" pitch helical kit for P3's in N6 and we ran in wheat, corn, and edible beans with great results.The factory has shock kits for R42 thru R72 only. I have installed shocks on rear feed on all models now. I like to put smaller tention drum in when I put shocks on these older machines to give more clearance under drum. Shock stabilize movement of drum which prevents banging, slugging, and plugging.