Back to the drawing board... stock low dollar 360
The specific carb is a step backwards. I'm a firm believer that EFI has it's place, but it's not on old cars. That's just me because I consider the smells, the tuning and retuning, and the maintenance as all plusses to owning an old car.
But in this case - a DP of any size will require some very specific tuning to get as responsive and "right" as a vacuum secondary on this application. This is a mild engine. The extra squirter and power valve is overkill for what he has, and the low stall and low rpm use that it predominantly gets will be negatively affected too. So it's a lose-lose. I'll go out on a limb and say it will "feel faster", but the track times will show otherwise.