There are a lot of motor oil related questions here on moparts.com. A quick search going back two weeks netted a few of the following:moparts.com - Another Zinc in oil question...... moparts.com - Anybody,your option on synthetic motor oil for a 440?moparts.com - Break In Oil? moparts.com - Best oil to use in re-built 440?
FWIW, my personal opinion and what Iíd recommend in selecting a motor oil for high performance flat-tappet use.
1) Try to not be afraid of spending a little extra money
on that quart of motor oil and get a good known high performance oil thatís already high in zinc. You spent a lot of time and money on your engine, why skimp on the motor oil?
2) Avoid aftermarket motor oil additives
. Such additives have been known to upset the chemical balance of an already blended motor oil causing such things as oil foaming. Save money by not buying the extra additives and leave the oil blinding/formulating to the experts. That money spent on additives could be going towards a high quality motor oil thatís backed by a manufacturers warranty. Using additives may void the lubricant warranty if an issue does arise.
3) Motor oils that are too thick
rob horsepower and affect performance. Try to go as thin as safely possible. For example, a friend of mine races his car in the 10.90 second bracket. He uses a high quality 10W-30 motor oil and has outstanding wear numbers from his Used Oil Analysis (UOA) report. Try to never assume that a high performance engine must have a 40-or-50 grade motor oil to survive.
4) Time to shoot myself in the foot. Do as much research
as you are comfortable with doing on this topic and try NOT to depend as much on the opinions of others. This includes internet experts, salesmen, and even engine builders. There is a lot of misinformation out there and many good sources as well. Personally find out what makes since to you and go with it.
5) After you find a motor oil your are comfortable with and have used it for at least a couple of oil changes, the best thing you can do is get a Used Oil Analysis (UOA)
. A UOA can be had for about $20-25 from a number of sources and can reveal things like actual wear from your engine. It can also tell you if there is excessive fuel, coolant or dirt in your oil. Finally, a UOA will tell you if the motor oil you selected is worth continued use. It could be that a specific brand or type of motor oil is not best for your application.
Below are a few informational sources that might get you on the way in the quest for the best oil.
Good luck! Hot Rod: Flat Tappet Cam Tech - Righting the Wrongs Bob Is The Oil Guy.com/forumsFlat Tappet and Camshaft Lobe Lubrication[/color