"As best possible" is often used in informal speech, but it's not grammatically correct.
Here's why:
* "As best as possible" uses the comparative adjective "best" correctly. It's comparing the effort being made to the highest possible level.
* "As best possible" is missing the comparative conjunction "as" after "best." It should be "as best as possible."
Example:
* Incorrect: I'll try to finish the project as best possible.
* Correct: I'll try to finish the project as best as possible.