There is a lot of scientific data here:

ZDDP Industry Tech Information for Oil Additives & Cam Lube from ZPlus (zddplus.com)

ZDDP

I chose to use ZDDP plus mixed with standard Valvoline 10-40. My current thinking is to reduce the ZDDP content at the 500 mi mark per comments Ted has made re to much of a good thing. 



.150 Stroked Y-Block:327.25 ci @ >1hp per ci  

                                Are you still using Shell Rotella 15w40 or something else?

I have the same info,verry good info. when I was working the co had oil forsale at a discount. the shell desel oil had a statement, do not use in flat tappet gas engines as will cause  came failure

           HI, I've been noticing guys using different oils in their cars. What is wrong with Shell Rotella 15w40. I remember a few years back everyone was using it. I still do. What has changed? Thanks.

That 20 minutes of run time at a higher than idle rpm helps to ‘burnish’ the cam lobe / lifter interface thus helping to seat the lifter to the lobe for the long haul.  The higher than idle rpm during the break-in process ensures that adequate oil is being thrown on the camshaft.  If there is a wear problem occurring, it typically takes twenty minutes for that to be noticed and/or be a measurable amount.  Rest assured that if the camshaft fails during the camshaft break-in period the engine oil being may not the culprit with the wear issue originating with something mechanical like inadequate lifter to bore clearance.  Here’s a link to a more complete list of items contributing to camshaft wear issues.

Camshaft and Lifter Failure Causes – Eaton Balancing

Lorena, Texas (South of Waco)

For the Ford Y, I typically recommend using a conventional grade oil with at least “30” in the viscosity rating (i.e.: 5W-30,10W-30, 10W-40, etc.  Nothing less than “30”as the shear property of the oil is reduced thus inhibiting the oil’s ability to help the lifter to rotate.  The viscosity of the oil must be selected based on the various bearing clearances rather than on what rings are being used on the pistons.  Zero issues in regard to the oil viscosity with metric rings as long as the cylinder wall finish is correct for the particular rings that are being used.

Lorena, Texas (South of Waco)

So, is the routine 20 min./higher-rpm break-in run then done largely in order to insure that any problem is recognized while in the shop (as opposed to out on the road), thus preventing subsequent collateral engine damage? Maybe that routine was developed due to a past period of poor quality component parts availability (and improper lubricant choices)?

6 VOLTS/POS. GRD. NW INDIANA

Ted, do you recommend using something lighter than 40 or 50 wt. with metric rings?

lube oil reference
I have info that came from speed talk, regarding extensive test results on 90% of oils available at time of tests,by a engineer from California who purchased 1pint of multiple engine oils race oil to diesel lab oil that should not be used in gas engines.tests wher performed in a lab.
if ther is a interest I would send a copy  to 1 person in the us  who would share with those from y blocks forever. as I live in canada the cost to send this info those in us is brutal esp
with our 73c us dollar
my email  is  ct1940@shaw.ca. will make 1 copy of all info to 1person who can distribute to  interested blockers isa

Is anyone using Mobil 1 0W40 European Formula or 10W40 High Mileage? Mobil recommends them for flat-tappet cams because of their higher (not too high) zinc & phosphorus content.