I can tell you exactly what it took to run 12.4's@108 in my '71 340 Cuda back in 1985>
Stock motor, 10:1, stock 2.02 heads unported, DC..590" SFT cam, Strip Dominator intake, 850DP, 1.3/4" race hdrs, 4200stall manual 727, 4.30's, 10x28's, stock 340 L/springs clamped@front, Mp performance shocks...