You've fairly much got the roundhouse punch on multiple carb info.
The most important work done on six cylinder carb sizing and calibration is the Argentina Six cylinder engines, specfically the old OHC conversion to the Nash in line 232 six. When it got OHC, it got sent to South America, and the wild Southerners played with the 5000 rpm rev limit engine, and were able to resolve venturi sizes for engines in our rev ranges, 3500 to 5000 rpm.
Chrylser Australia too made some 260 degree cam, 265 sixes that reved only to 5000 rpm, and the carb venturi sizes were screwed down to serve a 248 hp engine. Its in this area that Weber DCOE 45's impress the most. Similar issue was the 1960'S DCOE 42 Maserati GT3500
(Not listed below, but I know that the 32 mm 42 DCOE carbs flowed more than the 33 mm venturi 40 DCOE; Vizard noted that DOCE 45's with 32's also flowed better than smaller carbs with 33 venturis. The Argentine and Italian and Australians used Weber Italy to help them really unlock those lower rpm in line sixes.
"Weber Carb Edjumakashun" from Sat Feb 20, 2016
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That ideal size graph for venturis on a IR/POP system again...
I got the lower rpm range line sorted back in 2003 after some slueth work from Alfa Romeo and one French carb tuning site where they used a 5000 rpm Weber IR/POP line.
I haven't plotted that line, but its four 5000 rpm points are at
400, 28
475, 31
525, 31
550, 33
600, 34.
At 475, 525 to 550 cc per cylinder, the carb venturi size is rounded to the nearset mm, and they program uses the emulsion tube to control best fuel trim. When plotting, 525 should be 32 mm.
I just pop that into Excel, and it gives you a linear regression to solve for any cylinder capacity between the ranges in the graph.
The ranges for a big 635, 688 or 725 cc cylinder 232, 250 or 265 aren't on the charts I've seen.
Chrylser Australia had the the 248 hp at 4800 rpm E37 265 (38 mm venturis),
or 280 hp at 5000 rpm E38 (40 mmventuris )
or 306 hp at 5600 rpm E49 (40 mm Venturis )
http://bringatrailer.com/2010/10/16/cyl ... mi-6-pack/
listed as having a 5000 rpm power peak, and being a 38 mm venturi at 725cc. The Gran Routier Renault Torino with 232 and reving to 4700 rpm at the power peak, 35 mm. So there is evidence to establish the 5000 rpm line pretty accurately.
The lower blue line is for our Fords with IR/POP system at the 6000 rpm power peak rev limit, but Alfa Romeo has the 5000 rpm rev rang worked out
I've used the following Weber call size jets from another website application. Each graph is a generic one for 1.6, 1.9, 2.1, 2.2 and 2.4 liter DOHC Alfa Romeo engines.
Twin DCOE 40 Weber with 28 mm chokes for a 1.6 liter DOHC Alfa Romeo engine= 144 cid Ford Falcon six reving to 5000rpm. 115 micron Weber =152 cc/min=115 microns is a 45.28 thou jet.
400 cc per cylinder at 5000 rpm = 28 mm ideal venturi size
Twin DCOE 40 Weber with 31 mm chokes for a 1.9 liter DOHC Alfa Romeo engine= 170 cid Ford Falcon six reving to 5000rpm. 125 mircron Weber = 201 cc/min=125 micron is a 49.21 thou jet.
475 cc per cylinder at 5000 rpm = 31 mm ideal venturi size
Twin DCOE 40 Weber with 31 mm chokes for a 2.1 liter DOHC Alfa Romeo engine= 188 cid Ford Falcon six reving to 5000rpm. 125 mircron Weber = 201 cc/min=125 micron is a 49.21 thou jet .
525 cc per cylinder at 5000 rpm = 31 mm ideal venturi size
Twin DCOE 40 Weber with 33 mm chokes for a 2.2 liter DOHC Alfa Romeo engine= 200 cid Ford Falcon six reving to 5000rpm. 135 micron Weber = 251 cc/min=135 microns is 53.15 thou jet.
550 cc per cylinder at 5000 rpm = 33 mm ideal venturi size
.
Twin DCOE 40 Weber with 34 mm chokes for a 2.4 liter DOHC Alfa Romeo engine= 221 cid Ford Falcon six reving to 5000rpm. 140 micron Weber = 275 cc/min=140 microns is 55.12 thou jet.
600 cc per cylinder at 5000 rpm = 34 mm ideal venturi size
Here are flow figures for Triple DCOE carbs with the best trumpets fitted to the ends. Its based on flow through two carb barrels.
40 DCOE , 24 mm, 202 cfm at 1.5" Hg = 286 cfm at 3.0" Hg
40 DCOE , 26 mm, 241 cfm at 1.5" Hg = 341 cfm at 3.0" Hg
40 DCOE , 28 mm (Fiat 2300S), 279 cfm at 1.5" Hg = 395 cfm at 3.0" Hg
40 DCOE , 30 mm, 316 cfm at 1.5" Hg = 447 cfm at 3.0" Hg
40 DCOE , 32 mm, 336 cfm at 1.5" Hg = 475 cfm at 3.0" Hg
40 DCOE , 34 mm, 346 cfm at 1.5" Hg = 489 cfm at 3.0" Hg
40 DCOE , 36 mm, 350 cfm at 1.5" Hg = 495 cfm at 3.0" Hg
45 DCOE , 32 mm, 324 cfm at 1.5" Hg = 458 cfm at 3.0" Hg
45 DCOE , 34 mm, 376 cfm at 1.5" Hg = 532 cfm at 3.0" Hg
45 DCOE , 35 mm, (
Torino GR) 397 cfm at 1.5" Hg = 562 cfm at 3.0" Hg
45 DCOE , 36 mm, 418 cfm at 1.5" Hg = 591 cfm at 3.0" Hg
45 DCOE , 38 mm (E37 Pacer), 438 cfm at 1.5" Hg = 619 cfm at 3.0" Hg
45 DCOE , 40 mm (E49 Charger/
Tornino 380 Motor w TC), 444 cfm at 1.5" Hg = 628 cfm at 3.0" Hg