I personally think with a heavier car as yours, I would guess a 505 on pump gas and some edelbrock rpm heads and around 250@050 or so solid lifter or roller cam and I think you would be there. Porting the heads would help too if low 11s are the goal. There's a big difference between high 11 and low 11s. I don't have any real world experience with the big block quite yet so this is all an educated guess.