Good grades of castor include Klotz Benol racing castor at http://www.klotzlube.com, SIG Mfg. repackaged AA castor at sigmfg.com and Castrol M (overseas, not sold in the U.S. unless you want to buy most of the barrels or a shipload). Use a good castor and find one of these available in your area. Klotz Benol has a higher film strength than regular AA castor and is great to protect the bottom end of an engine in contest engines, like for boat racing, etc. Hope this helps.