>>> import itertools
>>> for a,b,c,d,e,f,g,h in itertools.permutations(range(1,9), 8):
...     if a+b==9 and c+d==7 and e-f==1 and g-h==3: break
...
>>> (a,b,c,d,e,f,g,h)
(1, 8, 3, 4, 7, 6, 5, 2)

total 8! = 40320 possibilities, the speed difference should not be noticeable if properly programmed.