I've messed around with 4 barrels on several 261 Chevys and a 302 GMC.I got them to carburate quite well after some working with jetting.But I was never convinced a single carb on an inline 6 is the way to go.2 or 3 carbs should be better than one for fuel distribution.
On an engine like the old Chevy and GMC having several shared exhaust ports you might think exhaust temperatures might vary quite a bit.

70 Triumph 650 cc ECTA current record holder