I used the .557 in my old 440 that was in my 63 as it was a mild 10.0 comp 906 headed pump gas street eng. Also have the .557 in my sons 400 Dart and both have run 11.40's at 116 and 117. My 63 is 3700 lbs and my sons Dart 3550.
My brother went 10.0's with a .030 over 400 (406) in his 2600 lb 68 Cuda as that 400 had Eddy RPM heads and a Team-G with a dominator. Ron