Van der Sar, currently suffering from flu, is debating whether to retire from football at the end of the season.
United have continued to be linked with several goalkeepers despite signing Anders Lindegaard from Aalesund.
But Kuszczak, 28, is determined to become the number one - or move on.
BIGGEST NAME
He said: "I know I have not got the biggest name in the world, and I do not want this to sound arrogant... I think I am good enough.
"I have talked to the boss (Sir Alex Ferguson) a few times and he said we will see what happens at the end of the season.
"I know that in the meantime if I get a chance I have to play well because that is the only way I am going to impress him.
"If Sir Alex Ferguson decides I am not good enough, then I will look for another club.
"Everything is open now. I am realistic about my situation. It would not frighten me to take over as Edwin's successor. Why should it? I am not new here.
"If I play for this club long term I will be really happy because that has always been my dream. I came to Manchester to try to be a top goalkeeper for many years like my idol Peter Schmeichel."