Engine timing mechanical

Never assume any timing marks are "correct". Don't forget, for the "LA" smallblocks alone there are 3 different timing cover designs (left-side cast, right-side cast, bolt-on tab) and then the dampeners that are supposed to line up with those. Add to that balanced, and unbalanced dampeners. Some companies make just two dampeners that "fit" all those different engines! Obviously they won't work for a lot of engines. Verify true TDC with a piston-stop, mark the balancer, and install a timing tape if required.
EDIT:
(oh crap, I just realized this in the big block section. Well, almost the same problems crop up with those too.)