I have a SBC 383 recent rebuild with ~300 miles on it with flat tappet cam, 10.5:1 compression, Holley 750cfm etc. The cam was broken in with Rotella 30W and a bottle of ZDDP additive for extra protection. I am running a 7 qt oil pan, HV oil pump and a larger "truck" filter that fits this SBC (AC delco PF1218 or equivalent). At most I put a few thousand a year on this car and will be doing the oil change each spring. I am in the south so I am guessing if I don't drive the car in the winter it will at worst see temps in the 60s. I have posted my scenario on another board regarding what oil to use or at least to understand the thinking of my builder and thought I'd try posting on this site that specializes in oil !! My car is coming up to its 500 mile oil change and the builder wants me to use 7 qts 30W valvoline conventional oil with 1/2 quart of lucas oil stabalizer. I have been doing a lot of reading and it "seems" like 10W30 should be fine for my application, but I am in noway an expert ?? Anybody have any idea what the SAE 30 is suggested or could it be just what was used in the past ???? As far as using valvoline I feel like that is what the builder has been using the last 30 yrs along with the lucas..just stuck with what works for him. I would like a bit more flexibility and would like to understand if I really "must" run the straight weight vs mult-weight oil. Thanks.