Mark - this issue has been debated many times, and will likely be debated many more times.
Since I do this for a living, I will offer the opinion I have offered many times in the past.
One adds additional carburetion for functionality because:
(A) one modified the internals of the engine
(B) the original carburetor is too small
(C) to increase the volumetric efficiency of the engine
So:
(A) you didn't
(B) it isn't (and your Carter 2100s is an excellent replacement)
(C) with a perfectly stock stovebolt 6 you MIGHT gain 6~8 percent efficiency improvement because of better cylinder fill IF YOU DO EVERYTHING PERFECTLY! (proper carbs, proper tuning, proper synchronization).
Your term was "significant". If you consider 6~8 percent significant, then go for it.
Be advised if you do a less than perfect job it is possible to LOSE performance, perhaps as much as 20~25 percent.
Or as Jerry so tactfully
stated, basically eye candy.
Jon.
