The CFM calculation (CFM = D × RPM × VE ÷ 3,456) is not divided by the number of carburetors for IR. 375 CFM total is not 125 CFM for each of three.
For reasons too lengthy to explain, three individual carburetors for an L6 can, and should, be much larger than three carburetors on a common manifold.
Except for the fabrication, the Weber DGV 32/36 is an excellent choice for IR. Other choices include Rochester 2G, SU HD6, Stromberg 175CD.
Panic, the problem I see with 2gs and possibly some of the others is tuning power valve opening. 2gs Use a wound spring that has to be over come by vac. The hillbilly way to tune the is clip the spring and I have done it with success on a single 2g on a 350 but using that method for tuning to closely match 3 on a IR manifold makes me nervous. In fact in looking the tuned spring is the problem with 228/28 Zenith's and the Stromberg BXOV. I believe that is part of the reason 97s are so popular is the plunger for the accelerator pump opens the power valve. 94s open with a valve like a standard 4150/2300 so it could be tuned closely on vac. The 2 Stromberg Bxov-2s I have are a matched pair for a dual single bbl set up but for a 500 cubic inch fire truck engine. It is doubtful the power circuits will match my needs and having various springs wound with the coil count, length and K I need will be a bit of a challenge. 94s are readily available, the Jets are common and the power valves are available but they certainly aren't 4 times bigger than the cfm needed for a pair of cylinders. We flowed a zenith 228 11 with a 30mm Venturi at 1.5" of HG at about 120 cfm dry and a 94 at 150 cfm dry. Not sure what a 1-7/32 Stromberg will flow but it does have a bigger Venturi(30.95mm) so it may flow about 6% more.
