Dear Karim,
You asked "I own only the mcu typ with the larger 4kb flash memory. AT89c451. Will it work ? "
You probably meant AT89C4051 and my simple answer is
yes it will work but upto 2kb and provided :
the Blowit or any one of the scores of programmer
detailed in net is planned,assembled and used by highly
experienced people like Charles or the undersigned.Newcomers even with couple of years of experience are always advised to set their priorities:
is it making a programmer or learning,writing and testing codes on actual applications.
But the way you say you have one mcu I see your mind is made up.So you may not be confused with these facts.
Regards
A.S.Rudra