I have been running 5 qts m1 10w30 and 1 qt lucas hd oil stabilizer in a 6.0 lq4 engine that has some lower oil pressure in hot weather. What would my actual viscosity resemble with this mix? I plan to switch to a 5w40 syn or 40wt euro syn most likley mobil or pennzoil. I am averaging 15 psi hot at idle and as low as 12 on straight 10w30 syn in 75+ temps. With the lucas it stays 18-23. Cruising 60-70 it stays 35-40 psi no matter what i pour in.