I am going to change oil in my new Corvette tomorrow for the first time. Eventually I will go with GC or Redline, but I still have 5 quarts of M1 SS 5W-30 in the basement that I need to use up first. Since the LS1 in the C5 holds 6.5 qts. oil, I was going to mix in 1.5 qts. of M1 15W-50 to up the viscosity in the mix a little. Any thoughts??