Today, a stock 5.0L (302 c.i.) Ford Mustang GT engine is rated at 412 hp normally aspirated with all the EPA goodies. In testing by the car mags, they consistently come in higher at the crank and about 400 hp. at the rear wheels. And they will easily last 100k+ miles with simple normal maintenance.
In 1965, a Shelby Cobra took a cast iron 427 c.i. (7.0L) big block from Ford's truck group and a lot of Carroll Shelby magic to get around 420 crank hp. that could last a whole F.I.A. race or the 24 Hours at Daytona.
Times have changed.
Yup. Back in the day we were very happy to get 2.5 hp per cubic inch. Now I go to Summit Racing and spend aobut $2k and do it very easily. You are right times have changed.