CFM-wise you'd be fine either way.
The stock 230cid/140hp carb is about 140cfm (at 1.5" Hg).
Way too small.
My rule for carb CFM (at 1.5" Hg) is, "double your horsepower" - that's how much CFM you need. About 10% less than that works fine. Even less will work, too, you will just lose top end. Sometimes way MORE is ok too if it is a progressive carb or a light car with steep gears.
The 32/36 Pinto "270cfm" Weber is about 200cfm at 1.5" Hg.
Not quite enough for a 230cid but bigger than even the 230/155hp HiPo carb which was about 185cfm. So that would work fine.
But you could be just fine going bigger, my experience is same as Twisted's. I've run and clocked CFM's from 390 to 450 to 500 to 625cfm on my stock 250, no correlation between et/mph and CFM, even though they all were a bit big for the 170hp engine. I will say though, the only ones I could stomp on off the line without a "gasp" of air were the 390 and 450cfm Holleys. So if you ever plan to upgrade to a 292cid or build the 230 up, then the 390 Holley would be a better choice.
Depends on your plans -
