Howdy Back Cocacolaman:
I have never done this, but it makes sense so long as you-
*get an Autolite 1100 or 1101 without a Spark Control Valve in it. That means a '68 or '69 1100. The down side is that these carbs only come in the 1.1" venturi size, which is the size previously used in 170s. 200 = 1.1" venturi = 185 cfm. 170 = 1.1" venturi = 156 cfm.
The 1101 was used on the '69 250 engine only. It would be Non-SCV and have a CFM of 210. This would be a great choice if you can find one. It is visually identical to the 1100 of adapting would be the same except for TB and bolt spacing.
*You will likely need a carb to manifold adaptor from an early 200 to orient the carb correctly. It may need to be made from scratch or a stock one modified.
If you're ordering a carb from Pony specify a High Performance 1100 for a 1969 200 engine. It will have no SCV and a 210 CFM. And it will be pricy!
The Holley #1946 is a terrible carb to work on. It is very encumbered with feed back systems and limited tuneability. I doubt that it flows more that 170 CFM.
Good luck and keep us posted on your progress.
Adios, David