This is a great thread! I was just having this conversation last week with a buddy I went to High School with. In Auto mechanics class I took on a project of doubling the horse power of a 283 Chevy small block out of a station wagon! Advertised HP was a whopping 195 HP! I was planning on putting this engine into a 1973 Vega Hatchback! The amount of time and parts I had to put into this project in order to attempt this was a great lesson and adventure!
I wound up close to $1500 costs (in 1976) and with High School shop equipment I finished it with a little over 300 HP (normally aspirated) and that was about max I could get out of that old iron block! It was a work of art!
Now with that being said! in 2008 I bought a brand new Chevy Impala SS with a 5.3 (basically same size of my finished 283 in the mid 70s) From the factory that impala had the same HP of a worked 283! With about the same amount of money in 2010 I did some mods to my Impala and am pushing almost 400 HP out of essentially the same size engine that I worked on in High School!
I think its great what they are doing now a days with HP and torque! I hope it gets even better!
Got a neighbor who bought a Camaro last year! 450 HP and a six speed manual! OMG! The amount of money and work we would have had to do to achieve that back in the day!