Do you
Grind your own crank?
Rebuild your own rods?
Set your own clearances?
Balance your own crank?
Do your own valve job?
Grind your own camshaft?
Bore and hone your own block?
Deck your own block?
Line home your own block?
All stuff you don’t do, that you can’t do without the machines and tools, so the guy who did the 318 didn’t do anything trick.
I used to make the rod throws as light as I could, so I could reduce the OD of the counterweight as much as I could. Then I woke up, reduced the OD of the counterweight and added one more stick of Mallory, rather than screw around and lighten up the rod pins. The better money was spent reducing the OF of the counterweights.
So again, the engine in the magazine article wasn’t trick. It would be very easy to put that over 500 HP, and you maybe could do it with the cam they picked.
A decent set of edlebrock heads or some Chinese heads would easily put power what they used in that build.
It’s not trick by any stretch of the imagination.
