Hemi , 440 or supercharge small block?

Since you plan on spending some $$$$, and you want some power, why not go supercharger gen 3 Hemi for power, economy & reliability so you can actually drive it once you spend the money.

On the fence about my Dart, want to get away from the 110 that it needs with the iron heads, so do I keep the 340 and do it for a 4th time or change up to a 6.4 crate

It is your car and you need to decide what works best for you

Any option you listed would be cool, but how much power does one really need?

Blowing the tires away at will might be fun for a short time, but my daily driver does it with my crappy winter tires (yes I need to upgrade them) but it sucks to go to accelerate and the damn thing just spins the tires or worse comes around on me turning a corner