My thoughts are to use 10-30 and do not change oil as the cam lube you instaled at assembly should stay in for at least 500 miles. A filter change after a short drive will tell you if there is a problem. and there will be stuff in the filter, even in a new engine. The lighter oil will ensure lots of early splash to lube cam.

Yes I used straight 50. Guess I messed that up too. Regardless, its got 20/50 now

Richard: Just a question?  Noticed in your earlier posts, that you said you started the new engine using straight 50 W oil . Was that recommended by someone? It isn't usual to do that...

Paul

Richard, sounds like  you are okay this time. I had 1 cam failure years ago that I was fairly certain was caused by lifters that weren't heat treated correctly. Some lifters from another source failed because they were made of junk material that was heat treated to the correct hardness but the substrate was soft and wouldn't support the hard surface.
 With regard to cams, I think the most common problem is lack of taper. In this case the lifter will only hit in the center and not rotate. I have seen 2 failures that I believed were caused by lack of taper.
One of the recent problems we have seen or heard about is poorly made rocker adjusters. The ones in question look like Ford self locking adjusters but require a jamb nut. The surface tests harder than original Ford adjusters but the underlying material is soft. I have seen these totally worn out in 50 miles.
Probably the most valuable tools to use during cam break-in are your ears! If at all possible, have mufflers on the test stand, dyno or however you have it mounted. If you hear any clatter of ticking that seems to be getting louder, shut it off. Check the lash. Look for metal in the drain back recesses near the rocker arms. According to Harvey Crane, if the cam is going to fail it happens in the first 2-3 minutes. Don't force the 20 minute break-in on an engine that is getting louder and louder. I like to have an open breather on the engine. Slight wisps of smoke are normal. A steady stream of smoke from the breather is a sign the engine is burning oil internally. This indicates hot metal. Not a good sign.
I had an engine on the stand that started to get a louder ticking sound after a few minutes. I found a rocker with .015" more lash than normal. Because the wear on the cam was slight the cam grinder was able to grind the one lobe and with a new lifter in place the engine was saved. Had I forced the break-in, the lobe would have gone flat and all the metal would have gone through the engine.
I have shut off quite a few engines before the 20 minute period was up and never had one fail upon restart.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Update:   Ran it again  2000-3000 RPM  Engine sounds great. Drained the oil, dropped the pan, cleaned out some powdered iron oil not much really.  Inspected the cam and lifters, they look fine no wear.  Cylinder walls look good.
Push rods spin as they should, so I think I will be on the road shortly for 50 mile run.  
Thanks for all the advice.
Pictures to follow.

Hi, any update?

Cliff

Thanks Meteor,
Pretty much did everything you suggested except oil and gas in the carb. Great idea by the way.  Prepping for another stationery run in. New oil, filter, and using an old dizzy drive to push the oil through the system.  If I don't get any more loose rockers then I will drive it. 
Thanks for all of your support. 

By the way:
All kinds of spooky stuff on the internet about this topic so its not just a Y block issue.  Most blame the metallurgy or lack of proper heat treating to cam and lifters. I have no idea but regardless of the out come I will push on. If I have to rebuild I will approach the break in with the center valve springs removed. After all we cannot go to hydraulic lifters like all the others.  Some of the cam grinders offer nitride for an extra hundred bucks.  Seems odd to me that option isn't standard on all solid lifter applications considering the consequences ,. Regardless too late for philosophy have to deal with the problems at hand.  

i agree with charlie on the oil. if you have lubed the cam lobes with the cam suplyers stuff.. my aproach to startup is do not do it until you can put some miles on. at the very start pre lube the engine till oil is coming to the rockers,then use a mixture of oil and gas down the carb so the valve guids get some lube,make sure  no water or oil leaks ,go for a drive and very the speed and drive for 30min you should be ok. after this re set the valves.  again.  if you start the car then leave it for months you ar increasing the ods for problem. i have a spare engine all built for my 57ranchero, i do not tighten the rockers down as why leave valve springs compressed. as well you want the molley cam grease on cam lobes and lifters for initial run in.Like others have noted you will get someparticles in the filter. breakin is a topic that has maney vews,you only know who is correct down the road. good luck

Thanks Ted,
Slept on it and am resolved to deal with the problem or lack there of what ever it takes. I'll run again today and see what happens.
Checking your list I see why failure happened the first time:   Items 2,3,4.  

After twenty minutes of running, I typically look for no more than 0.002” variance in valve lash between the valves.  While iron heads will not vary the lash much from cold to hot, the aluminum heads will grow approximately 0.007"-0.008" from cold to hot so that must be taken into account but the variance between valves should still be minimal.  If I find an excessive amount of variance, then I take note of the valves in question and after running the engine some more (5 minutes tops), then recheck the valves.  If there’s an additional increase in lash, then there’s a problem.  Valve lash checks on my end are performed with the engine not running.
 
Here’s the link to the list of items that contributes to cam/lifter failure.  Any one or a combination of these can cause a problem.
http://www.eatonbalancing.com/blog/2012/11/06/camshaft-and-lifter-failure-causes-2/ 

Lorena, Texas (South of Waco)