I use a 900 myself. They were built with aluminum stalk rolls, and had failures mostly because they'd break at the spiral cone, and_or the rivets would egg out the holes. Replacements were steel as they should have been from day one. On heads of the 8-900 type, the snoots may be thin by now and new gather chains, upper and lower sprockets, stripper plates and a full knife set may be in order. I like the old 900 just fine. The 1000 series uses what some call a waterpump style stalk roll support bearing for those who don't know what a grease gun is. The 8-900 have zerks, altho some guys retro'd theirs to the new style sealed bearing. If greased regularly, those bronze bushing type bearings in the old style heads will run a long time before replacement is needed. Check for wear carefully. Don't buy the head twice!