500 hp is pretty easy these days.
Mostly because the airflow technology is better understood.
I sitting here reading an article were they took a 150,000 mile Chevy 5.3 pickup short block assy, added a good set of cylinder heads and cam and got 484 dyno hp.
I have a 1976 Chevy powered Jeep CJ-5 with about 525HP. Don’t ask my why. I’m not sure I know that answer.
Cam, headers, e-fans, intake, tune and my trailblazer ss put down about 400 all wheel hp. That’s about 500 crank.
You could take a junk yard iron block 4.8/5.3/6.0 a step further and drop a turbo in. Instant 600-800hp for a couple grand (if you do it yourself).
Wonder how long it’ll last...
Did you see this? 2 V-6s welded together into a V-12.
It was posted here a few weeks ago.
http://ls1tech.com/forums/conversions-hybrids/1643786-v12-ls1-build.html
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.