https://www.oilspecifications.org/api_eolcs.php

This stated, all the new oils, SN or CK-4 have reduced Zinc Phosphorus (ZDDP)as they have found that it clogs catalytic converters.

Our old flat tappet cam engines needed this to prevent high pressure wear in this area. Approximately 1000 to 1200 ppm.

Now some of these oils have introduced a molybdenum base into the oil to replace the Zinc wear additive, some have not as modern overhead cam engines do not have the same cam loads.

If your running a conventional unmodified engine you should be fine.

If you are running a performance engine you likely need to do something.

Race oil is high in ZDDP but has no detergents - it's made for one race or a few trips down the track, not the cruise on the highway and around town for three or more months in a crankcase.

There are ZDDP additives for conventional motor oil, but like Frank stated you don't know how they will mix with your oil additives.

My solution - mixing a race oil and conventional or synthetic oil of the same manufacturer of the same weight. Most race oils have 1600+ ppm ZDDP and new conventional oil 600 to 800 ppm ZDDP. So a 50-50 mix will get you there. Most all manufacturers keep to the same oil stock base and additive packages.   

Isn't it rather, well, silly to blame the oil because the engine went when that oil was in it?
If there was an issue could it not have been the oil a couple of changes ago or more that caused it - OR it was simply ready to go for other reasons?
You don't say "what blew" - could be totally unrelated to any oil.

This topic has been VERY recently hashed over at length - and several other times as well.
Just use a good oil and a good filter and be done with it. 

(besides - you are in a very real sense asking what religion is the best)  

I use synthetic Mobil One in my 4.0 in my Eagle and use just a good quality oil, not totally brand loyal, in the other cars. Never lost an engine in any car I've owned or ever worked on in over 40 years.

On an overhead cam we are talking 1:1.

Our old rocker cams have a valve train that multiplies forces from rocker ratio. So my 85# stock springs with 6:1 rockers are transferring 510# to the cam.

How many iterations of oil engineering have happened in the last 10 years? - 4.

So your Pens, Shell, Mobil ... have all changed 4x in 10 years and 10 years ago is when hi performance engine people started to notice problems. I wonder why they developed roller lifters in that time?

So what is everyone's spring load to the cam based on Franks numbers posted above - simple math.

Should you think about doing anything - your car, your call. 

 

Adding stuff to your oil can be a BAD idea. The actual protection is added DURING the oil processing - and adding it later can actually REDUCE the protection the oil gives. That's been PROVEN.
It's NOT NOT NOT the zinc. Zinc doesn't add protection, the phosphorus n ZDDP is what does it.
You do not need additives if you use a decent oil.

The needing to add "Zinc" is one of those urban legends that just to this day seems to keep growing and has a life of its own.

If extra stuff was needed then thousands of engine rebuilds done by shops and people like me would e failing day after day. 
It's not needed. Choose a decent oil and use it and skip the bloody additives. 

I have a 280H in my 360, a Comp X-treme in my 4.0 and in my 390 and I use straight oil with no additives - and the same for many other people I know.

Why did they move to roller lifters?
Simple- if anyone thinks about it - because the Japanese did - and because it was necessary to squeeze more miles out of engines and still meet emissions.
Think about it - competition to extend warranties, the requirements to meed MPG rules, reliability competition when the foreign companies came in and said "we warrant our engines for 100,000 miles" and a few more reasons I could think of. Technology, warranties, competition and so on. It was not because of the reduction of "zinc" in the oil.
Roller lifters have been around for a very very long time - not just since the EPA stepped in. 
Foreign car makers were doing such things before we were because fuel cost a week's wages over there, small cars and engines winding up to 10,000 RPM to get the SAME HP as American made engines - think a bit. Honda was kicking our HP butts with engines half the size winding up crazy RPM and it all requires less friction and more efficient engines. That made for light cars that got good MPG and lasted a long time. We finally caught up.......... but not because of oil changes.
No one wants to believe engineers, they believe AMSOIL and others who SELL these crazy additive products and make a mint on them. They believe the fellow who builds a car in his garage and loses a cam and blames the oil and then puts in a new cam, adds ZDDP and doesn't lose a cam. Anyone stop o think the guy lost a cam the first time because of HIS mistakes?? No,, blame the oil.

http://www.corvetteforum.com/forums/c6-tech-performance/3656635-engineering-test-data-on-high-mileage-motor-oils.html" rel="nofollow - https://www.corvetteforum.com/forums/c6-tech-performance/3656635-engineering-test-data-on-high-mileage-motor-oils.html

http://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/" rel="nofollow - https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

Not that anyone will believe me as I'm the idiot that just comes in here to rant. Well there's a reason - no one will believe science, they prefer to believe cousin Bubba or stuff they hear about a cam failure.
Been at this for about 45 years and have never lost a cam or lifters - but then I pay attention to important details.

Interesting to some may be the fact that by ADDING crap to their oil they may be REDUCING protection.
Remember, these things are often best added when the oil is made or blended - to add them later can cause you MORE wear, not less. And there's no good way to prove it unless you do the engineering testing, losing an engine or not losing an engine is proof of nothing.

I could post a couple of other great links but why waste my time - someone will just flame me for dissing their beloved additives anyway. 

Bottom line - use a good quality, name brand oil and filter, change as recommended and take care of your engine and it will do what mine usually do - go over 100,000 miles without major trouble. 
It truly is that simple.

You are absolutely correct in picking a high psi rated oil over ZDDP content alone.

Absolutely correct about aftermarket addatives.

Have a read and your thoughts of SN afterwards for your 360 or in this I6 section a high lift cam on a 258:

http://www.widman.biz/uploads/Corvair_oil.pdf 

This may or may not change your mind but it's an interesting read, at least for people like me.

Agreed, Same here (20w-50) but Brad Penn 

Farna's advice from a petroleum engineer is very good.

My oil:

Quaker State Defy high mileage 10W30. It's a high ZDDP, low detergent synthetic blend that is not expensive. It isn't super high ZDDP (1000 PPM Zn, 800 PPM P), but it is more than standard API SN and plenty to protect all but the most radical camshafts and springs. It has fewer detergents than standard API SN to help that ZDDP do its job and to not over-clean older engines that have sludge and varnish buildup holding the gaskets together to prevent leaks. Still plenty of detergent to keep the engine clean given proper oil changes. 

Behind my rear seat, I've mounted a 55-gallon drum of a mixture of new oil composed of 1 quart from all available retail brands, plumbed directly to the oil pump pickup through an assembly of filters from each major filter brand.  Then, as oil returns to the sump, I have a pump which returns it to a second, 55 gallon drum, mounted on a roof rack, which contains only waste oil.  When I get through about 3/4 the barrel of fresh oil, a light comes on, warning me I need to top off, and I head home to pump in more oil from my pre-mixed underground storage tank.  At that time, I also offload the waste oil for recycling in various ways.