The break-in oil won't hurt anything,
it's not necessary really I this case not for roller lifters
{depends on rockers, if they aren't roller tip or roller truniun, might help some etc.}
{zinc should be used with a flat tappet, {mushroom lifters remember them} solid or hydraulic camshaft & lifters}
especially not necessary on a full roller set-up either,
some parts like the push-rods still have a metal to metal contact @ rockers & lifters
also timing chain & gears, even rings etc., all need heat cycles to harden,
albeit it might be overthinking, why they recommend it,
some engine builder still recommend high zinc phosphorus based oils
even after break in & even with rollers...
I remember a guy would put a some caustic liquid soap detergent in his cylinders & oil
I can't remember the brand now, he was adamant about always doing it,
to a new build, but he'd run it for a time on the trailer, while towing even sometimes,
before going to the races...
Remember him saying it broke in the moly rings way faster,
"allegedly" so it wouldn't burn as much oil, not sure if it was true,
his builds were always nice, high dollar engines too, spinning them too the moon...
Old Trans Am racer guy Wes from Concord Ca.
{can't remember his last name, he was a buddy of my step father Bob/Pontiac guys}
& he never had any major engine failures racing...
OK back on topic
for quicker break in maybe ?
some won't ever recommend synthetics either
old habits & old-school engine builders
some guys still run 70 wt or diesel oils too
it might just be old habits, old practices & they like a certain oils/brands
& don't veer from what they actually know has worked in the past
maybe they are in the camp better to be safe than sorry
like I said it won't hurt anything
