It's rather difficult to reach that figure and still run on pump gas. In that case cubic dollars are going to come into play. By you saying you want to run on pump gas makes me think you want this to be a street machine. If so then trust me, you wouldn't like it on the street as it wouldn't have real nice street manners and if your running a automatic it would require around a
4000 stall converter and some pretty steep gears. If this is a drag car it will make things easier, but still it will need more compression to get there than pump gas could handle. As mentioned to get there easier you need more cubic inches. going with a 383 is one way to do so, or you could look into purchasing the 3.875 stroke crank and making a small block 396 would make it much easier to reach that goal.