I was watching an episode of Graveyard Carz today where they were doing the dyno runs on an original Daytona and a 2016 Hellcat. Of course the Hellcat blew the Daytona away. The comment was made repeatedly about technology being the reason. So what is the difference? The basic short block is still the basic short block. Technology would have to have effect in head design, fuel delivery (EFI), ignition management, and camshaft design. So....what would prevent all of this technology (minus the supercharger) being applied to a 383 and ending up with a 500 hp 383 that gets 22 mpg on the highway?
The guys at Graveyard are not engine builders so don't put too much stock in what they say. I have a 514 engine sitting in my shop that makes 900 hp. It has EFI and 8 coils so I can adjust fuel and ignition for each cylinder. If that engine was in a car with a 6 speed transmission it would probably get decent mileage going down the road. With EFI you can just lean it out and advance the timing and get the engine super happy at cruise.
Modern engines have a lot of work put into them to make them efficient. Most of those tricks can be applied to older engines. Tighter clearances, lighter weight oil, better head design, computer controls, etc. About the only thing you can't do with the older engines is retrofit variable cam timing. The variable cam timing really opens up the door to building an engine that idles like a sewing machine but really rips at WOT. With fixed cam you have to just live with a compromise for the overlap and it hurts you either top end or bottom end.
