What’s the difference? I made 545 at 5200 with a 408 on hydraulic rollers. It would have made close to 600 if the customer would have switched to solid lifters and used a cam to make power to say...6500. That wasn’t a hard build either. A basic 408. The hard part was getting the owner off the internet and to stop listening to the internet hero’s, which at that time I had no idea this **** even existed.
So...I can take the very same heads, stick them on a 318 with equal compression and a cam with timing for the smaller displacement and make the same power as the 408. It just won’t do it at a John Deere RPM, nor will it be at Comp Eliminator RPM.
Of course, that engine doesn’t count because there are no time slips for it, but it was with the carb, ignition, headers and water pump he was using.