In episode 175 of Semantic Mastery's weekly Hump Day Hangouts, one participant asked if Google will flag as spammy a new website with no links if it gets link juice from over 2000 referring domains at once.
The exact question was:
1. I recently found a really strong, topical relevant expired domain. I want to use it as a 301 redirect to my own target website. However that target website is extremely new (2 months old and literally no linkbuilding on it so far). Will google detect this as spammy since there currently are no links at all on this website and now the link juice of over 2000 Referring domains would come at once. On the other hand It's only 1 redirect, not planning to do any more redirects in the future (You could make the case that I just moved the domain name of the company, so it would make sense in the eyes of google. However I am concerned since the expired domain really has a lot of backlinks)