No. No new threshold. You dug up and posted Steve Dulcich's Dyno run on a STOCK 340 to prove a point. Yes it did make 317 HP with just a bigger carb change. Would it be easy to make just under 1 HP per cube for a 318, NOT easy but it can be done. But not if you Flamingo* the 318 to stock CR and heads.
*Flamingo is where they handcuff your left wrist to your right ankle. You really can't do squat.