[steelcomp]

We noticed considerable leaning in the mid range with the 1850s on the dyno, but as I stated in my earlier post, if you do a simple mod they work seamlessly. I never had a problem with them not opening all the way either, if treated to a spring change. (That's why they make different springs for them)

As far as the "CFM" chart... that dosent mean a thing in the real world. It's a guide line for minimums (for a given VE), not maximums. Honestly, a motor is only going to move a given amount of air for a given dispacement at a given RPM, and it really dosen't care how many carbs you put on it. Carburetors pose a restriction, even at the proper CFM for a given engine/RPM. Now, of course you won't force more air into a naturally aspirated engine with a bigger carb. What you will do is reduce the restriction which will allow the engine to "breathe" better. As always, there is a trade off when going to bigger carb(s). But as long as there is ample air signal to the carb for it to provide proper atomization, the engine will use what the carb will allow it to use. For example, if you took the chart and your average performance motor, say a 496" BBChev, turn it 7500, that chart calls for aprox. 1100 cfm @ 100%VE. Why do we get another 65-70 hp by near doubling that? (two Holley 1050s) We might be at 110% VE, which with the formula, would call for 1220 cfm. Still not close.
See what I mean? Honestly, the better carbs would be the Ford 715CFM vac secondary carbs. Ford's engineers didn't just pull those out of a hat. But a 427 at 6500 only needs about 880 cfm. according to Holley. I've talked to their Tech guys a few times, but they don't offer information "outside the box", so I quit calling.
If it were me, I'd get over the antiquated dual four barrel thing and put a good single on it. Lets face it, it's a replica.