340 or 408?

I don't get this easier idea, it's gonna take a certain carb, intake, heads, cr, headers, cam etc.. For each to make 500 hp. What's so hard about getting the right parts for a 340 vs a 408 ? Doesn't take a Nascar level build to get 500 hp out of a 340 bet the parts are very similar.
I believe the 408 can make the same power as the 340 (at 500 level) with less cam and less compression. I consider that easier.
Even easier, with less of everything..... with a 512.