JBM,
My Kirkhan 427SC Cobra had 4 Webber's on it's 427 FE. They looked really bitchin' but there were two big problems. They made big power but not smoothly. They were like an on/off switch. All or nothing. My Cobra would idle and it would go like hell at WOT. But at part throttle it would stumble no matter how much tuning we did. Next problem....they HATE any type of air cleaners. Even a loose screen killed a lot of power. Driving in AZ on our dry roads with lots of dust getting sucked into my $40,000.00 Keith Craft 427 was really distressing. I finally gave up and went with a 4-bbl Holley carb. The engine made the same max power but it was smooth and ran great with a K&N filter.
I love the look of Webber's but they are a major PITA. I would never attempt that again. Cheers.
Chip