Yeah they definitely could, but they likely detuned the Vantage to keep it from cannibalizing sales from the DB9. The Ferrari engine is much more of a high rpm screamer. If the Vantage 4.3 revved to 8500 rpms like the F430 does, it would probably produce close to 450 hp.

But it's not just the peak horsepower. The F430 is a more extreme car in other ways, and that comes with tradeoffs. The Vantage 4.7 updated some of the things on the 4.3 to make it perform better...lightweight pistons, enlarged valves, lightweight flywheel, etc. But it still isnt designed to be as raw of a car as the F430...but you can get it closer if you are willing to make some tradeoffs.

 

Such a shame its not coming over. Got a feeling its got to do with safety, eg seat sensors, crumple zones etc.