Back in the early 80s when I was poor did it several times with no issues. Had no idea about break in either. Start, idle, drive. Would never consider it now.
That's how every car was started way back when and still today. Bust it off an go. You think they were gonna take time to break in every flat tappet camshaft the oils back then had a higher zinc that left the factory? Not just no, but hell no. Of course, the oils back then had a higher zinc content, too. Most spring pressures were mundane to say the least.
