I put one of those Comp Nostalgia cams in the L71 2 years ago. No issues.
Also put one of those Nostalgia 30/30's in the DZ motor last year.
That being said, it really worries me every time I put a motor together- with all the guys reporting flat tappet cam failures for the last 10 years.
I also know some very reputable local race engine builders who do this for a living who have told me the same thing- never lost a cam in my life until...
But I do also see other folks reporting hydraulic roller failures.
So it's a crap shoot I guess.
I've been very lucky- but I go to pretty extreme measures to hopefully circumvent such a situation from happening.
First thing- it's very important that you verify the lifter convexity and the cam lobe taper.
Ensure that the lifters do not bind in the bores- and that they do spin.
Most folks do not check this- and it is critical.
Most do know to remove the inner valve springs, and use a good quality break-in lube- applied liberally to all the lobes.
Make sure your timing is set statically, and you are using a known good carb.
Prime the motor until you see oil pumping out of every pushrod.
And fill the carb float bowls with gas- so the motor fires immediately and does not crank and crank before starting.
And of course, as most know- be sure to vary your RPM range over 2000-2500 for the 20 minutes of break in time.
Personally, I use the Driven break-in oil, and dump it immediately after the engine is shut down- and then cut open the filter to inspect.
I then put about 100 easy miles on the car, with high zinc oil- then dump the oil again and cut open the filter one more time to inspect.
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