The twin 500 carbs are just like twin DCOE 42's with 35 chokes.
As long as the power valve, channel restrictions, and pump squirters are the right size, , it'll be just fine. People use a modified side draft Holley 500 90 hp 1340 cc Harley Davidsons without a problem, and the Weber ADM 34 has been replicated by the old BMW 3.0s and some MB 280'S.
Fiat 2300S's ran twin DCOE 40 and 38's with there little 139 cubic inch I6 engines way back in the 60's. The reason this works is the same reason a single Weber DCOE works on a Mini. The fireing impulses and 'sucks' of the engine dont overlap enough to create cross scavenging between cylinders, or any major issues with fuel distribution. If you can get the fuel to the engine quickly, you can then run more advance, smaller pump jets, bigger venturis, bigger jets. Everything gets easier with dual carbs on sixes, not harder.
http://www.pbase.com/adriank8/silnik_f2300scoupe_po_remoncie
Twin carbs are easy to tune as long as you don't make a swan neck intake mainfold which sloshes all the fuel air mix against the walls to create a puddling, stageering mess. The stock EFI upper intake is on too much of a curve, and the mix will condense around the 90 degree bend. The 12 inch runners are 5 inches too long. Generally, the best runner lenght for a six is about five to seven inches, but most runners are limited by packaging constraints.
The alternatives either won't package
(This is very common with triple Webers)
, or
the outer cylinders run lean 2-bbl staged
or
2-bbl unstaged.
You have to be ability to run from rich to lean easily without too much fuel having to be sloshed around the intake manifold. That way, it'll lean cruise at 14.7:1 on the open road, while it will richen up to 12.5:1 in all cylinders when the jandall is given.
I wanna see P100's machine work well. If little DGV 32/36 carbs from Cortinas can work on anything from 1275 Minis to 200 Falcon engines, two willl work sweetly on a 250, esepcially with that manifold. The stock 1600 2V Cortinas did about 88 gross hp with this carb, so putting them on a 162 hp EFI engine won't be a problem.