Engine Oil

According to this company report yes its fine to use with its adequate ZDDP levels and other additives. May weep and use more of it than thicker oils but by golly I'm very pleased how well its kept ferric fur off sump magnet and improved the finish of cam and lifter and rockers rib on stem wear zones. You could always add some straight weight 50 withit own ZDDP to up the thickness some and use up your 40 weight supply slower.
http://forums.pelicanparts.com/porsche- ... p-etc.html

here's some data on Heavy Duty Engine Oil's to take in.

http://www.acccc.net/index.php?option=c ... &showall=1