Case in point this engine shows exactly what I mean. It will depend on how much vacuum your engine makes and how well the carbs vacuum reference is matched to your engines requirements.
http://wright-here.net/files/articles/phr_1109_sbo/phr_1109_sbo_ocr.pdf
"The intake port is way smaller than the original. , think the factory was 152 cc and now it's down to 145 and it's much higher. It's got a small cross section of 1.91square inch~ es]." Final flow numbers ended up around 195 cfm on the intake and 170 on the exhaust. Though not huge peak flow numbers. he claims they were almost at those numbers by .200-inch lift. Just perfect for limited camshaft and rpm range applications.
They made 1.37 HP per cube with only 195 cfm peak flow. They made 2.2 HP per cfm truly remarkable when you think about it. Its at 316 CI and uses an 800 carb.
Its making very good torque for a small cube engine with a small port and a big carb. Now if you hogged those ports out to 180 cc what do you think the vacuum difference would be for the same rpm that the carb would see? If nothing changes in the short block the pistons draw on the port at those rpms is now less is it not? The piston now has to displace a greater area. So what happens to the vacuum the carb see's now and how does the calibration now affect the fuel delivery? How do you compensate a lower vacuum reference now? You play with calibrations......Or you could go to a smaller carb could you not?
Here's a good thread with so much insight it's required to be read many many times over to be really understood.
emulsion question
Now what happens to the vacuum at the T/slot when you put a bigger carb on? Then think about why Mopar used a spread bore design and you realize you get the best of both worlds.