Sorry is this is a repeat, but I did a search and could not find a dedicated thread to ZDDP additives we might use. I am going to try:
Lucas Engine Break-In Oil Additive - TB Zinc Plus
they say

"Protects camshaft lifters and valve train during break-in period of motor.
Excellent for flat tappet camshafts during break-in or as an additive to any motor oil to prevent premature wear.
Exclusive blend of extreme pressure additives.
Add one bottle with every oil change to increase the zinc content of your motor oil.
Designed for race applications requiring additional extreme pressure additives."

Yes the bottle says its for break in, but this clip from their website implies we might use it regularly.

I'm thinking of 8oz (half bottle) per oil change with my usual Rotella.

Comments?

 

Y blocks with stock cams load the lifters and cam very lightly compared to modern engines. The guy that helped me on the first rebuild (a chevy racer) was paranoid about new lifters every time: I've got a couple of sets of old lifters with nice convex crowns on the wear surface, compared to the dished lifter that comes out of a small block chevy. I've been driving y-blocks for 45 years, I've never replaced a cam. When I assembled an engine, I put a little 30w gulfpride (60-s) or havoline (73 up) oil on the cam and lifters. It's pretty sticky. I never cranked the oil pump on a 292, it's a trick I learned on small blocks( 255, 302, 5.0) The first rebuild, in 1968 I got the oil driveshaft installed wrong and no oil pumped for about 10 starts until I had it hauled to the shop for an expensive lesson. That cam is still in it, and the crank/bearings lasted until the tailhousing wore out on the transmission, probably 250000 or 300000 miles When I did have the crank turned, it had only .0018 clearance, then the dummy at the shop turned it .011" undersize. Use what you want for assembly, it probably won't help or hurt much.

 

indianajo - it's not a matter of what "used to work" for you since ZDDP was just recently removed from oil. It is now a matter of what you need to do to keep things working. The main problem area is lifter/cam interface since it is the heaviest loaded part in the motor.

Midnite Cruiser - you are headed in the right direction looking into ZDDP additives. While Shell says Rotella still has 1200ppm of ZDDP, it is recommended to have between 1600-2200ppm so it's still lacking what we need for non-roller cams. New cars with roller cams don't need it, most diesels are now roller cams and they don't need it. Race engines with roller cams don't need it. You now have a very small percentage of the population driving a flat tappet cam motor so the oil is leaving us.

Some good places to look for ZDDP? Hardcore racing oils (I have switched all my non-roller motors over to Brad Penn racing oil, I like the 20-50. With this you don't need any additives). It is made for these cams, costs a few bucks more but does work. You can also add something called ESO that is available at your local GM parts counter to your favorite oil. It's about a pint bottle and you add one every oil change. Another cheap and easily found source is plain old STP. It has ZDDP in it and you can get it about anywhere. What you don't want to do is put additives in oil containing high levels of ZDDP. It's not recommended by the racing oil manufacturers since it can upset the chemical balance.

We need to educate ourselves on this. Circle track racers started noticing a problem with solid lifters about 2 or 3 years ago and found oil wasn't just oil anymore. Some very knowledgable people have done a lot of work to find and correct this problem on $30,000+ motors, we can use what they learned.

SPark

 

According the Corvair Flat Tappet Oil article, phosphorus (the anti-wear component of ZDDP) levels over 1400 ppm contribute to long term engine wear and increased engine deposits. Levels over 2000 ppm can lead to camshaft spalling. The author of that article recommends the use of a good CI-4/SL Heavy Duty Engine Oil (HDEO) to protect flat tappet camshafts and a good CI-4/SL HDEO contains 1000-1200 ppm of phosphorus.

There is no need to add more ZDDP to your usual Rotella, especially if you're using Shell Rotella T CI-4. I would use an HDEO rather than a racing oil because HDEOs have better detergent additives and can go longer between oil changes.

ACCCC Engine Oil Article