Haas will run its first upgrade of the season on Kevin Magnussen's car at the Hungarian Grand Prix this weekend.
Haas is the only one of F1's ten teams not to have upgraded its car in any significant way this year and had originally targeted last weekend's French Grand Prix for its debut.
Several costly Mick Schumacher crashes earlier in the season pushed the timetable back and has left the modestly funded Haas team enough parts for an upgrade on one car only.
The team is giving the upgraded package to Magnussen as he is ahead in the championship in 11th with 22 points, while Schumacher is in 15th with 12.
The Budapest race will provide Haas with a good opportunity to do a like-for-like comparison on the old and new cars across the weekend.
Spares will also be at a premium for the American team, meaning any accident for Magnussen in the practice sessions or qualifying risking his participation in the grand prix on Sunday.
Haas has remained a competitive team in F1's midfield despite not upgrading its car to this point.
In a statement ahead of the race, Haas boss Guenther Steiner suggested the team is quietly confident of a good step forward.
"As many people know, we waited a bit longer to bring our upgrade to track because I think we still have good pace. Now what we want to do is put performance on.
"What exactly it will do, I don't want to say because I don't want to jinx it, but we know what it should be doing from our development. We'll just have to wait and see what we can get out of the package."
The team hopes to have the upgrade on both cars after the three-week break which follows the Hungarian Grand Prix for the following race at Belgium's Spa-Francorchamps circuit.