I have a 2005 Mustang Gt with roughly 85k miles on it. I put cams on about a year ago. I noticed my car now burns 1 to 1.5 quarts of oil now between 4k mile oil changes. Before cams, it burned about half a quart to 1 I currently use 5w20 Ford Motorcraft So I am thinking of upgrading to Royal purple HMX. Now the only thing I'm wondering is, would it be a better idea to use 5w30 or 5w40? I know the car is heavily modified so heavier oil will definitely be helpful in preventing wear. Is this safe for VVT? Any other recommendations as well?