Back in the day, up til '72 (changed mid year or later); It you got tires, pinion snubber, and maybe some slapper bars- abody 340 beat a bbody 383. Add headers, cam and carb; tune it- watch out.
Heck, with a 318 2bbl swapped to a 500 Holley, then jetted down, stiffer springs on the factory cam...