Haas used in the last day of testing the Melbourne spec Ferrari engine.
if they used in the first race , they will be battling for points.
Not only that, they are also using Ferrari chassis parts and most of bits and pieces on the car look strikingly similar to Ferrari.
I would say it's a big unknown with the Haas.
I wouldn't be surprised whether they end up at the back (young team, many many details that can go wrong and hurt the results, management mistakes, overall lack of experience, relatively limited budget...) or the middle of the grid (direct or indirect help from Ferrari, strong EPU, presence of some very smart and experienced engineers that worked with other teams in the past, etc).
The latter scenario would be awful news for McLaren.