340 stroker build will this make our goal

We did a 408 for my brother, only 10.2 on the comp and the duration is @ 50 254/256 and the it sounds good, but not that radical the big stroke definitely eats up the duration, iron heads pump gas on 10 inch tire, runs 11.00 in a 68 Dart
Do you know what weight/gear ratio for the car and what kinda rpm he was turning