Hello, in the middle '70's I put 40 dcoe's on my toyota 20r, and am still driving everyday with 597,000 miles, same carbs several rebuilds on the engines, and remember having teething problems about the same as yours. I got to experimenting with the emulsion tubes and looking at the position of the orifices and just thinking of how the fuel flowed, be one with the flow, and tried the F2 variety, even though everyone said they were for alcohol they worked perfect, no stumble you can mash the throttle in 4th at 1200 rpm and it will pull clean. just my experience
mike