sha1 64 hex with only 8 variables

[MisterY]

Hi all

I have the following constellation:
SHA1(64 bytes) = hash

Known are 56 of these 64 bytes as well as the hash value itself. Is it possible to set up a masked attack with the following specification?
- a length of 64 bytes
- 56 bytes are constant, only 8 bytes are variable
- the possible input is the whole byte range, 0x00 to 0xFF

Thanks a lot for your thoughts