AJ's Opinion; what size SBM do I need

I'm not buying that the 383 is to the Big Blocks what the 318 is to the small blocks.
Back in the fifties or sixties you could get a 383 with two four barrels on it. And I have yet to see a roadrunner with a two barrel from the factory. I know you could get a 383 2 Barrel in the charger but I believe you can get a 318 in a charger also. I'm talking early 70s late sixties.
383 is no dog or boat anchor.
I would say the 350 big block or the 361 would be comprable to the 318 in status.
The only two four barrel 383 was the 343hp in the 62 plymouth, and maybe the dodge. There is some discussion whether it was factory available, or a dealer installed option only. 62 wagons with the 343 horse 383, were badass, stock eliminator record holders for years!