Hi Ron,
Maybe we need a Webers vs 4 Barrel forum

Ok yo can shoot me now hahahah.
The biggest advantage a 4 barrel has over Webers is ease of tuning. This comes from the vast body of knowledge available both locally and at the vendor level for 4bbl setups.
There are precious few people around that can get all the performance out of a set of Webers. We should be cloning them now for future generations.
I'm living with the Weber learning curve right now, after paying darn good money to a couple of different shops, both perported to be Weber experts.
What become apparent is that Webers don't like what 4bbls like. Not the cam and not the ignition timing either.
Webers are like a pure analog multiport fuel injection system if there was such a thing. Not unlike a vinyl record vs a cd. No argument the cd is quieter and easier to use, it just doesn't sound as good as a record (on decent equipment).
Webers provide each cylinder with an instantaneous shot of emulsified air/fuel mixture and will normally out pull a 4bbl in torque as you have noted. If they're falling on their faces at high rpm then something isn't right with the motor and or carbs internals, not that the carbs aren't right for the application.
So were back to body of knowledge, expensive dyno time and equally expensive Weber jetting parts. Each carb has two main jets, two idle jets, two emulsion tubes, two air correctors, one accelerator pump exhaust valve and two venturies (chokes in the Queens english). Times four carbs and each part has to work in harmoney with the rest. No wonder people are afraid of Webers!
Once the FMS392/48IDA is running at its' best, the carb, engine and tuning specs will be posted on the forum. Perhaps we can get to a series of engine combinations with known to work Weber set ups.
The car deserves Webers, however a good 8 Stack system like Waynes from Very Cool Parts is my other choice. Hey, at the price of gas these days you could pay for the cost difference in fuel ecomomy alone!
Cheers