340 Vs 360

Why would they use the same heads
The conversation evolved fron rat bastid telling me that a lower torque higher rpm engine will always make you go faster than a higher torque lower rpm engine, even if they are equal horsepower.

Since cylinder head is the main limiting factor to horsepower, and displacement is the primary factor in making torque. we started talking about the hypotheticals of less/more displacement with a given cylinder head.
the ones I seen win were stroker 400 fords and stroker modern hemis. It's probably cheaper to build smaller since you have to build less overall power but nothing stopping larger engines to make same overall hp per cid.
Agreed, There's nothing stopping them entering with big cubes but it gets cost prohibitive.

A 414ci would need 574hp to make the same 1.388hp/ci as this 371 did. That's at the upper end of the potebtial of a small block on pump gas.

In the other hand, A 273ci mopar could be pretty competitive in this competition. It would only need to make a peak hp of 379hp to have the same peak 1.388 hp/ci.

I know which I would find easier and cheaper to built!

Our conversation wasn't about this competition
If that's the case there seems to have been a misunderstanding.
It may make more but who knows, a 414 already makes these power numbers with similar parts why parts messaged to get great power out a 371 gonna work better than they normal do for the 414.
With similar parts, yes.
I do think it would take an improved cylinder head for a 414ci make 574hp @ 6000rpm and to still be making 555hp @ 6500rom.

With these heads power would be falling off well before 6000rpm.
Do you factor gearing in cause a 371 and 414 will be operating at different powerbands. You got to basically line up peak hp numbers then compare hp curves, that's how it would be on the track.
Absolutely.
Gear ratios are super important to keep any engine operating within it's powerband.