I'd agree with Russ here - the webers flow more efficiently than a 4 barrel on a common plenum all other things being equal, however, as has been pointed out the largest sizes run out of total flow capacity at high (500+) hp. One reason the webers work so efficiently on a single port (actually, two ports/cylinders per carb, one for each throat) is that the atomized fuel doesn't hit a bunch of hard turns and side walls and condense, staying more uniformly atomized in the right AF ratio. If you think about what happens to the atomized fuel coming out the bottom of a Holley as it flows directly downwards and then hits the bottom of the plenum chamber it partially condenses on impact, and does this again as it makes the twisty turns on the way to the cylinder. The IDF/IDA manifolds typically do a pretty good job of minimizing this partial condensing.
Of course, the technical papers on this topic talk about the re-evaporation of the condensed fuel on the wall due to the rapid flow of air past it, so, in the end the fuel does eventually make it's way into the cylinder, however, it's just not quite as precisely metered as in an IDF/IDA set up.
Of course, the technical papers on this topic talk about the re-evaporation of the condensed fuel on the wall due to the rapid flow of air past it, so, in the end the fuel does eventually make it's way into the cylinder, however, it's just not quite as precisely metered as in an IDF/IDA set up.
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This is where I started to get the idea that it may be worth a try, because in general if I can get the high HP and tune well, I should still get good to reasonable drivability. I hope to end up in the over 600Hp to 650 HP range with my stroked FE engine. The heads are probably flowing over 350CFMs now and I think I'll end up at about 375CFm or so. I think the biggest challenge will be finding the right cam right off the bat. I think if I have to test several cams, the cost will go nuclear.