I can only give you my experience. Mine is a Roush 427SR, it burned quite a bit of
oil. I pulled the heads, and had them checked. The valve stems were worn, and could actually see a "lip" at the beginning of the worn area. I had the valves replaced with feria's (sp) that were slightly larger. The heads were cleaned, new valve seats, up put back on the engine, and all is fine, no
oil consumption, no smoke when letting off the throttle. Runs really good, and I have no complaints.
Wish you the best of luck on your situation!!!