Whatever it takes / took? [closed]

Solution 1:

In the most cases you use "whatever it took" because it is about the past, however, it can be "whatever it takes" in the special/particular context when the present tense is used to describe the law, laws of nature, the universal rule, the phenomenon which occurs constantly when the universe exists. So, the context also determines the meaning, and the grammar just helps to express it.

Solution 2:

"Takes" is present tense and cannot be used here, but (as you note) "took" is awkward, so I'd rearrange the sentence to avoid the issue:

he was prepared to do whatever it would take to find investment.