it's wild right? i mean, i like HP just as much as the next guy but you absolutely don't need 400 for a nice cruiser.
new hemi 5.7's don't even have 400hp and they absolutly haul balls. in heavier vehicles no less!
i put "i gotta have 400hp" up there with the whole "i want a cam that sounds good" in the category of indoctrinated nonsense from magazine articles, tv shows and forum blather.
Problem with picking a random power number is even 25 hp can change the whole cost of the engine and or driveline. To get that next step might need a whole different engine parts list and different drivetrain.
Eg. A 360 can easily get 275-375hp with a lot of stock parts and driveline, 400+ hp 360 almost everything starts to need or should be modded/upgraded.