318 or 360 Roller Swap

You know Rumble. The differences between all these intakes on a 300-400hp engine is so small it's not worth the $ to replace one intake with another if it's a performer/RPM/air gap/LD340/LD4b
That's the likely range the OP is looking for. Spend an hour with a dremel or grinder and the port opening can be the same if it's that big of a deal to you. Sweat over $'s.

The performer 318 with 1hr or less work in the port openings put down 425hp on a 360 vs the air gap at 432hp IIRC

The big 340 port LD340 vs the small port LD4b on a mid 12's 340 auto car.... an incredible .02 et change and no MPH change... HMMMM

I've been around the dyno/track enough to know that the flow and port opening BS of the 340 vs 318 is mostly nonsense and minimal in actual performance. As you point out, what's BEFORE the opening is as important as the opening itself. You know when the Super victor put down a crapload more flow than an air gap. Then you put a SV on a somewhat rowdy 410 inch engine and the poorer flowing Air Gap kicks it's *** from bottom to top.

Same red herring BS as the 741 case bullshit that's been around for years.

The OP has the intake, why waste money on something else... funny how that works for one persons plan and not the other. :)

Other people and magazines will wastefully spend your money faster than anything! LOL