Just looking to see you guy's opinion on what oil to run in my 1966 Cadillac Deville with the 7.0L/429cid V-8. I am looking for something with the highest ZDDP but that is much harder today with modern oils. I am currently running MaxLife red bottle (semi-syn) 5w/30. Manual calls for 10W/30 but I am open to other grades such as 10w/40, 15W/40, 5w/40 etc but not 20w/50. My other options are to just add a ZDDP additive to regular oil to boost it or use one of the "vintage oils" available but I really would rather have something easy to obtain and not as expensive. Right now I am strongly considering the Valvoline VR1 oil...is that a decent choice? THANKS!