Hi everybody, will I open a can of worms? I just added about half bottle of Redline race oil 60wt because the level was a bit low, so with the sump full thats about 4.5 quarts of oil total. The oil in the sump was mobil one 15w50. I believe noise has gone down and the car revs a bit easier , despite the thicker oil. (vintage automobil, never lighter than 50wt... now the mixture is between 50 and 60 wt, towards 50wt..) is this just my imagination?