I've rebuilt a 66' 450 and I guess I'm looking for another opinion before I yank it out again. New pistons, valves,..it was running great..no smoke/leaks. After about 50 miles of running the right side started burning white/blue smoke and I mean alot! I took it home, grabbed a beer and let it cool down. (feeling very depressed/angry haha..) I took the plug out and I could see oil in the cylinder. Any Ideas? I'm thinking a valve guide but just throwing it out there.