What is your 60ft.?, it must be weak, i run 12.5s @ 104-105, so theres 12.5s in your car, i normally run high 12.5s with 1.79-1.80 60fts., mid 12.6s on 1.82-1.83. I think your problem lies in the 17K stall & 727 trans & "possibly" the 750, i'm running a 904 with a 2800 stall, 650dp, but with 3.73s.
Car looks good BTW, always liked the notchbacks