When you say wasim bowled in dead pitches, then you should also take record away from Indian and paksitani batsman than because record shows there are more dead pitches here and alot more runs are scored in Indian and Pakistan than anywhere else.

The fact is you adapt to the place where you learn. If Wasim had such a great record in Pakistan (and statistically still falls behind Ambrose) that means he doesnot pick as much wicket outside pakistan as ambrose does.

If we say Australia have been generally the best team in last 15 years and judge by the performace against them, then curtley still have staggering record against them.

27 test matches with mind boggling 128 wickets (almost 5 wickets per test match) at an average of 21. Akram only have 50 wickets in 13 test at an average near 26.

 If you say pitches in Pakistan are dead than Akram's record in Australia or that matter south africa is nothing to write home about. 36 wickets in 9 test matches at an average of 25 in Australia and in south africa it falls as low as 39. Compare that to Ambrose record 78 wickets in 14 test at an average of just 19 which is incredible.  ambrose still magages to pick wickets every 23 runs in south Afirca.  It is generally assumed that Australia and South Africa have been the best team in last decade or so.

Akram better performances have come against Sri Lanka, Westindies and New Zeland who in anybody's book are not the top side.

Another reason why amborse is better bowler because he is more consistent bowler than Akram. He has better record than Akram in every continent that including Asia which is generally considered dead. The table below gives how much run each bowler gives before taking up the wicket  (i.e bowling average)

                          Ambrose                                       Akram
In Asia               22.50                                             22.53
Africa                 23.76                                             30.02
Americas           21.19                                              26.88
Europe              20.77                                              28.73                  
Ociena              19.96                                              20.05
Home                21.19                                              22.22     
Away                20.78                                              24.61                

Shane warne in his top50 cricketer's put Curtley Ambrose in number 3 (although I am not that big fan of his rating ) behind Sachin and Lara, Steve waugh  always said Ambrose as the best bowler in the world. Lara always regarded ambrose as the best and said he was thankful that he didnt have to face him, Micahel Atherton always regarded Ambrose as the most difficult bowler to face.