Do you remember what cam you ran sweet combo.Not all that difficult but takes good parts selection, assembly and tuning. Check out the direct connection race bulletins for SB E body, they have builds and a layout of parts. Of course these are dated but you need to think of this as a system, everything MUST work together to include the engine, trans, U joints, drive shaft, tires, etc.
Back in the day a buddy and I built a 340 in a 74 Challenger with a mild cam, good intake and carb, headers and 31" slicks and ran 12.6 @ 109 mph. I think we were running 4.56 gears if I remember right and this was a 4 speed car.